environment: winxpsp1 + fb1.5-rc8
code:
[line 9] if exists (select 1 from rdb$relations where
rdb$relation_name = 'theTable') then ...

in ibexpert I get:

Invalid token.
Dynamic SQL Error.
SQL error code = -104.
Token unknown - line 9, char 6.
exists.

I can use a help on this.