camera error after replacing LCD digitizer

so i recently bought an LCD digitizer for my S3, i dismantled the phone and reassembled it on the new LCD. initially the first time i powered it up the camera worked and even took a picture, however after i put my thumb on the front facing camera, the phone said "camera error" and turned off the camera app. then using the Facebook app i could still take selfies, but then even that stopped working. so i opened up the case again. i unplugged the flex cable for the front and rear camera and rear plugged them both in and they worked initially and then again within 2 mins they showed the same error. now i again tried re-plugging both cameras but there is still a camera error. and no i dont think there is any software error.