Connect to a PostgreSQL table with kylix3

Hello:

I made a program to connect to three tables called 'pc104', 'sensores'
and 'pm500' on a postgresql database.
Everything was fine until I made some changes on table 'pc104' (drop
table, create the table again, added new values, etc)
Now when I make a SQLQuery object, if I make a query on table 'pc104' or
on table 'sensores', I get this error when I try to get the SQLQuery
object active:

Access violation at address 43A92782, accessing address 43B09774

Anyone knows why?

Thank you,
Carlos