Problems after customizing, patching...

Hi, i have a k770i. I customized it by adding elves, patches and stuff. However recently, it started giving me some problems. For example, sometimes when I try to take a picture, after you press the "shoot" button sideways, it just returns to homescreen, like it exited the camera application. Other times, i can't access my pictures. It shows them as broken picture files and cant open them. Other times, when i open a picture previously taken by camera, it may be corrupted, showing half of this picture and half of an other I might have erased. Finally, it got stuck and when I restarted it, a whole year's picture files were gone!!!! Good thing i had a backup... At first I thought it was a problem with the memory card... But I checked it with h2testw and it showed no errors. Anyone else with similar problems, or an idea about what's causing them? Could it be the modification of the phone?