Hi David,
while I can´t help with finding a repair center, my first impression was that it might not be related to the hardware if the buttons send weird codes. What do you mean by that exactly, weird midi messages?
The classic hardware error is when one button triggers many functions at the same time.
If you don´t experience that, and especially if previous versions worked fine, I suggest that you try re-uploading the firmware, to see if that might get rid of your error.
You can also play with rolling back to 1.03 and then reupload 1.04 etc..
Best,
Christian