Hiya,
Likely there is a CRC check within the proggy which detects if any bytes have been altered by patching. You'll need to locate this routine and disable it.
Realizing this, a good approach would be to...
Run an API monitor to log the file operation API's. CreateFileA, ReadFile, OpenFile, _lopen, _hread, _lcreat, MapViewOfFile... those are the main ones.
There is a good chance that one or more of these API's will be used to open the file / map it into memory so it can be read and the CRC calcuation can be performed. Once you've found the when and where from the monitor, set a bpx on the suspicious function. SICE should *hopefully* break close to the CRC routine.
If not, a backtrace between CreateFile (or whatever API it uses) and the error MessageBox could be another useful tatic.
Likewise, I'd suggest doing a search right here on the local Fravia mirror for CRC checks. There are at least a handful of essays on the topic which could prove insightful.
Hope this helps
Regards,
Clandestiny
