on windows you should find a pltcl.dll already in the PostgreSQL
library folder (e.g. C:\Program Files\PostgreSQL\9.1\lib\)
You can test the language creation with the following command:
createlang -U [username] -d [database] pltcl
Make sure your postgresql \bin folder is in the system path otherwise
the T-ACE_DB_manager won't be able to create the language for your
and the function can't be created.
I hope this helps.