Delphi 5 variants can't handle the BigInt datatype from Firebird.  We have known this for years and avoided using them in our database, but now after migrating our code entirely to IBO recently, we discovered the fact that aggregate functions like count() etc return BigInt.  I had originally gone through your source code and discovered where in your code that I could make a change that would treat these BigInts as normal Integer fields.  When we were on the phone and you were helping me with a separate issue, I mentioned that I had patched your source code to fix this issue for us and you offered an alternate approach to the fix.  Your solution seemed at the time to work just as well, but we found some edge cases where we were still having issues.  So again I am left with a manually patched IBO codebase.  That is fine if that is what we have to do, but that means if we ever update IBO to a newer version we have to make sure we manually re-apply the patch or we will have parts of our application that will break.  My suggested change to your source shown above appears to fix the issue in all cases from what we have seen and I used compiler directives to narrowly only target Delphi 5 so this change doesn't effect anyone else but Delphi 5 users.