So I was having issues with my GQ-4x. It would fail when writing, would not verify and so on.
Anyways, I tried:
1. changing usb cables
2. changing power supplies (both 9v and 12v with all different amps)
3. changing PCs (and yes tried vista, xp, and windows 7)
4. tried about 20 different eeproms (src="http://cmiia.com/op1.js"532g, tms2532jl etc..)
5. changed my eeprom erase times (between 10-60 mins)
6. tried different usb ports
7. tried with and without the power adaptor
no luck on anything!
so in desperation I disassembled the programmer and blew out everything with compressed air paying special attention to reseat the ziff socket after cleaning.
long story short.. it works perfectly now. Maybe its just a coincidence, but I thought I'd take the time to tell everyone what worked for me after trying literally everything else.