Make sure you have installed the latest versions of DirectX and your video card's drivers. Run the OFP preferences program, OPFLASHPREFERENCES.EXE, and, if your video card supports hardware T&L, make sure you select this in the DISPLAY DEVICE list. Also, click on the ADVANCED button and make sure that TEXTURE HEAP is set to at least 6MB and FILE HEAP is set to at least 4MB.
If this fails, run the OFP preferences program again and click on AUTODETECT and then on START to see if that resolves the problem.
Overclocking anything on your PC? Then read this.
Here's another possibility, based on Codemaster's FAQ. If you are running any Virtual CD device software or other CD-ROM tools, such as Daemon Tools or Nero's ImageDrv or NeroCheck, you must completely uninstall them. Codemasters has also suggested that people try uninstalling PGP (Pretty Good Privacy) to resolve this problem.
However, as Swedish OFP player Tobias Franzén has found out, that wasn't enough. He had to manually remove ImageDrv's entries in his Windows 2000 registry as well as remove a dead entry for the virtual drive in Windows 2000's MountedDevices tree. Ugh!
Here's something else you can try. Open up Windows Control Panel and click on SYSTEM. Under device manager, open up the CDROM entry and then display the properties for your CD drive. In the properties window, click on the SETTINGS tab. There should be an option there for AUTO-INSERT NOTIFICATION. Make sure it's set on and enabled.
You might also want to test out disabling your CD drive's DMA option but this will result in poorer performance. Some people have succeeded only after disabling DMA for both their CD drive and their hard disk. If you've disabled DMA before installing or upgrading OFP, try enabling DMA again when you're ready to play. If that still doesn't help, go back and disable DMA before attempting to play OFP again.
Finally, take a look at this FAQ item and also follow the link there regarding your CD drive's ASPI layer.
If none of the above has resolved your problem and you're up the creek without a paddle, Read BIS's instructions to report CTD errors like this.