Access violation in module COMP32P.DLL

I hope to get answer to my problem.
I work on project ported from Builder 1 to Builder 4. After 5 months
of plessure ....

If I put any breakpoint in the code programs stops with message
"Access violation at address 012775BB in module 'COMP32P.DLL. Read of
address FFFFFFFF" on very first attempt to read information from data
base. Without breakpoint it works o.k.

In the past I saw it twice and after rebuilding problem was gone.
This time nothing helps. I am desperate as after new features added I
need to work with breakpoints.

I ask for any ideas that can save me.