As stated above, the SRAM patching in the injector is based on ezgba (the commandline version, NOT the GUI version) which was created using information reverse engineered from GBATA, more or less. The error everyone seems to be getting isn't really a problem with ezgba, it's a problem with something on your computer stopping the injector from accessing the temporary directory it uses for storage when building the rom for injection.
Possible causes:
- Computer Cleaning Utilities
- Windows Defender or other Antivirus Programs false positiving ezgba
- Not running the injector as Administrator
- Windows SmartScreen false positiving ezgba
I don't know about the multicart of that game, but I know the individual games, only Spyro Season of Ice has trouble saving.
Spyro 2 Season of Flame saved fine for me otherwise. Have you tried doing 2 patches instead of 3? (1 for the cart UI, 1 for Season of Ice, and then leave 1 pass left so Season of Flame remains unpatched)