"Failed to map FH to vol"

[manser at clienta.ch (Daniel Manser)]

 Dear list,

 What do these messages mean? My client can't write and these messages 
 are filling up the nfs.log:

   [2011-06-14 13:38:42.826673] E [nfs3.c:724:nfs3_getattr] 0-nfs-nfsv3: 
 Failed to map FH to vol
   [2011-06-14 13:38:51.826871] E [nfs3.c:724:nfs3_getattr] 0-nfs-nfsv3: 
 Failed to map FH to vol
   [2011-06-14 13:39:00.827037] E [nfs3.c:724:nfs3_getattr] 0-nfs-nfsv3: 
 Failed to map FH to vol
   [2011-06-14 13:39:09.827248] E [nfs3.c:724:nfs3_getattr] 0-nfs-nfsv3: 
 Failed to map FH to vol
   [2011-06-14 13:39:18.827401] E [nfs3.c:724:nfs3_getattr] 0-nfs-nfsv3: 
 Failed to map FH to vol
   [2011-06-14 13:39:27.827578] E [nfs3.c:724:nfs3_getattr] 0-nfs-nfsv3: 
 Failed to map FH to vol
   [2011-06-14 13:39:36.827783] E [nfs3.c:724:nfs3_getattr] 0-nfs-nfsv3: 
 Failed to map FH to vol
   [2011-06-14 13:39:45.829407] E [nfs3.c:724:nfs3_getattr] 0-nfs-nfsv3: 
 Failed to map FH to vol
   [2011-06-14 13:39:54.828145] E [nfs3.c:724:nfs3_getattr] 0-nfs-nfsv3: 
 Failed to map FH to vol
   [2011-06-14 13:40:03.828344] E [nfs3.c:724:nfs3_getattr] 0-nfs-nfsv3: 
 Failed to map FH to vol

 Thanks,
 Daniel