Help me with modding please

Hello i want some weapons modes and i figured out that i need img tool, so i downloaded this one "Alci's IMG Editor 1.5"
than i fallowed some tutorials and i know that i need to open some gta file and put those files in and rebuild them etc etc ...
but there appears error: Failed to delede old img file , than i deleted them ... and tried again 100 times than it writes error: Failed to rename a old img file :S anyone can help please ?

Something wrong with Alci's then.
I am a proud loving user of Alci's and never had any issues.
Alci's is made to auto delete the old IMG files and replace them with the new. Might be that I always backup my files and so they're never in the IMG file when I mod it, but I've done it without backing up before, never had an issue. Re-install Alci's and try again.

damn i reinstaled it but still same problems :S is there any other editor that i can try ? :S