Bvis 4-50 and jvc projector

Hi beoworlders

I have a customer freind who I installed a Home Cinema system for all is working fine apart when he uses the projector the image displays lines and sometimes the picture blanks out, I'm convinced it's not the projector, but there is a gefen hdmi to cat 5 it's been working fine for the last 3 years question has anybody had this I'm guessing I could replace with an active hdmi cable that way no gefen no cat cable any thoughts