borked install - cannot downgrade

[brian <brian@xxxxxxxxxxxxxxxx>]

Linux 2.4.20-021stab028.24.777-enterprise #1 SMP Fri Jan 6 19:39:27 MSK 
2006 i686 i686 i386 GNU/Linux

httpd-2.0.51-2.9.1 & httpd-devel-2.0.51-2.9.1 installed as RPM.

I attempted to install php-5.1.4 from source only to run into something 
at the final step. I'd previously had 4.4.0 installed through RPMs on 
this machine and had removed them before installing the version compiled 
from source.

-- snip --
# make install
Installing PHP SAPI module:       apache2handler
/usr/lib/httpd/build/instdso.sh SH_LIBTOOL='/bin/sh 
/usr/lib/apr/build/libtool' libphp5.la /usr/lib/httpd/modules
/bin/sh /usr/lib/apr/build/libtool --mode=install cp libphp5.la 
/usr/lib/httpd/m odules/
cp .libs/libphp5.so /usr/lib/httpd/modules/libphp5.so
cp .libs/libphp5.lai /usr/lib/httpd/modules/libphp5.la
libtool: install: warning: remember to run `libtool --finish 
/home/bally/src/php -5.1.4/libs'
chmod 755 /usr/lib/httpd/modules/libphp5.so
[activating module `php5' in /etc/httpd/conf/httpd.conf]
Installing PHP CLI binary:        /usr/bin/
Installing PHP CLI man page:      /usr/share/man/man1/
Installing shared extensions:     /usr/lib/20050922/
Installing build environment:     /usr/lib/build/
Installing header files:          /usr/include/php/
Installing helper programs:       /usr/bin/
  program: phpize
  program: php-config
Installing man pages:             /usr/share/man/man1/
  page: phpize.1
  page: php-config.1
Installing PEAR environment:      /usr/share/pear/
[PEAR] Archive_Tar: PEAR_Registry: could not open filemap 
"/usr/share/pear/.file map"
[PEAR] Console_Getopt: PEAR_Registry: could not open filemap 
"/usr/share/pear/.f ilemap"
warning: pear/PEAR requires package "pear/Archive_Tar" (recommended 
version 1.3. 1)
warning: pear/PEAR requires package "pear/Console_Getopt" (recommended 
version 1 .2)
pear/PEAR can optionally use package "pear/XML_RPC" (version >= 1.4.0)
[PEAR] PEAR: PEAR_Registry: could not open filemap 
"/usr/share/pear/.filemap"
Installing PDO headers:          /usr/include/php/ext/pdo/

-- snip --

I then could not locate the PEAR binary. I realise that this might be 
better asked on a PEAR list, but it gets worse (though, if any 
recognises the problem, i'm all ears).

I did notice this line:

libtool: install: warning: remember to run `libtool --finish 
/home/bally/src/php-5.1.4/libs'

Which, if i'm not mistaken, would be the wrong thing to do, since that's 
just a temporary directory.

Being at a complete loss, i then attempted to downgrade to 4.4.0 through 
those RPMs i'd mentioned. They seemed to install fine, but then Apache 
complains upon restart:

-- snip --
[Sun Aug 27 05:54:14 2006] [notice] Digest: generating secret for digest 
authentication ...
[Sun Aug 27 05:54:14 2006] [notice] Digest: done
[Sun Aug 27 05:54:14 2006] [notice] LDAP: Built with OpenLDAP LDAP SDK
[Sun Aug 27 05:54:14 2006] [notice] LDAP: SSL support unavailable
PHP Warning:  PHP Startup: U1\xd2\x89\xe5WVS\x81\xec\xdc: Unable to 
initialize module\nModule compiled with module API=20020429, debug=0, 
thread-safety=0\nPHP    compiled with module API=20050922, debug=0, 
thread-safety=0\nThese options need to match\n in Unknown on line 0
PHP Warning:  PHP Startup: U\x89\xe5WVS\x83\xec\x1c\x8bu\x0c\xe88\xf9: 
Unable to initialize module\nModule compiled with module API=20020429, 
debug=0, thread-safety=0\nPHP    compiled with module API=20050922, 
debug=0, thread-safety=0\nThese options need to match\n in Unknown on line 0
PHP Warning:  PHP Startup: U\x89\xe5VS\x83\xec \x8bu\x0c\xe8xS: Unable 
to initialize module\nModule compiled with module API=20020429, debug=0, 
thread-safety=0\nPHP    compiled with module API=20050922, debug=0, 
thread-safety=0\nThese options need to match\n in Unknown on line 0
PHP Warning:  PHP Startup: U\x89\xe5WVS\x83\xec\x1c\x8b}\x0c\xe8\xfez: 
Unable to initialize module\nModule compiled with module API=20020429, 
debug=0, thread-safety=0\nPHP    compiled with module API=20050922, 
debug=0, thread-safety=0\nThese options need to match\n in Unknown on line 0
PHP Warning:  PHP Startup: U\x89\xe5W\xbf\x0f: Unable to initialize 
module\nModule compiled with module API=20020429, debug=0, 
thread-safety=0\nPHP    compiled with module API=20050922, debug=0, 
thread-safety=0\nThese options need to match\n in Unknown on line 0
PHP Warning:  PHP Startup: U\x89\xe5W1\xffVS\x81\xec\xbc: Unable to 
initialize module\nModule compiled with module API=20020429, debug=0, 
thread-safety=0\nPHP    compiled with module API=20050922, debug=0, 
thread-safety=0\nThese options need to match\n in Unknown on line 0
PHP Warning:  PHP Startup: U\x89\xe5VS\x83\xec \x8bu\x0c\xe8\x1dZ: 
Unable to initialize module\nModule compiled with module API=20020429, 
debug=0, thread-safety=0\nPHP    compiled with module API=20050922, 
debug=0, thread-safety=0\nThese options need to match\n in Unknown on 
line 0PHP Warning:  PHP Startup: U\x89\xe5VS\x83\xec 
\x8bu\x0c\xe8\x1a\x8f: Unable to initialize module\nModule compiled with 
module API=20020429, debug=0, thread-safety=0\nPHP    compiled with 
module API=20050922, debug=0, thread-safety=0\nThese options need to 
match\n in Unknown on line 0
PHP Warning:  PHP Startup: 
U\x89\xe5WVS\x83\xec\x1c\x8bu\x0c\xe8\x91\xbf: Unable to initialize 
module\nModule compiled with module API=20020429, debug=0, 
thread-safety=0\nPHP    compiled with module API=20050922, debug=0, 
thread-safety=0\nThese options need to match\n in Unknown on line 0
PHP Warning:  PHP Startup: U\x89\xe5VS\x83\xec \x8bu\x0c\xe8\xa5,: 
Unable to initialize module\nModule compiled with module API=20020429, 
debug=0, thread-safety=0\nPHP    compiled with module API=20050922, 
debug=0, thread-safety=0\nThese options need to match\n in Unknown on 
line 0PHP Warning:  PHP Startup: U1\xc9\x89\xe5VS\x83\xec 
\x8bu\x0c\xe8\xbf\xff\xff\xff\x81\xc32R: Unable to initialize 
module\nModule compiled with module API=20020429, debug=0, 
thread-safety=0\nPHP    compiled with module API=20050922, debug=0, 
thread-safety=0\nThese options need to match\n in Unknown on line 0
[Sun Aug 27 05:54:14 2006] [notice] Apache/2.0.51 (Fedora) configured -- 
resuming normal operations

-- snip --

Leaving aside my obvious n00bness here, the error /is/ pretty cryptic. 
Can anyone please shed some light on this? The modules all appear to be 
in /usr/lib/php4/ and php.ini is pointing there (extension_dir).

brian