>> error : "ISC Error code: 335544328 ISC Error message: Invalid BLOB
>> handle".

...

> here it is:
> TIB_SessionBase.HandleException($C83E84)
> ConvertDB('C:\old_data\old_db.dat')
> ConvertDBs('C:\old_data')
> Tform1.Button1Click(???)

I presume that ConvertDB is something you have written to read info
from a .dat file (what format?) and write it to the IB database.

Any chance you can post the section of that function where the error
is occuring - to give us some idea what you are doing?

Since there is so little in this callstack I am presuming that you
compiled the IBO libraries with debug information turned off. Would
it be possible for you to rebuild the libraries with debug on and get
the callstack again?

Perhaps you can run the IB_Monitor and post the relevant section so we
can try and see what is happening.

Sorry to be full of questions, but there is very little to go on at
the moment.

--
Geoff Worboys - TeamIBO
Telesis Computing