Error of text2ltree

[Vu Hong Thuan <thuanvh@xxxxxxxxx>]

I can't use text2ltree. Any suggestion? Thanks.

SELECT text2ltree('abc'). It's okay. But, got error if:

SELECT text2ltree(to_char(243, '09999999'))

***�Error�***

ERROR: syntax error at position 0 SQL state: 42601