Why does my anti-ubiquitin antibody visualization not work on my PAGE gel?
There are stable ubiquitinated proteins in mammalian cell lysates even if active proteosomes exist in cells. 

First, you might want to make sure that the antibody is applicable to WB. 

Then, you would ask if your WB system using the antibody works. You could optimize the condition using just 1D SDS-PAGE followed by WB. 

For the condition for isoelectric focusing, when focusing is completed, you get very high electric resistance, so you might want to monitor current after you change the voltage to 700 V. Current decreases gradually, and get stable at some level. But I do not know you can see stabilization by 700 V.

You also might want to check if major proteins such as actin form spots nicely at the expected pI. That could tell if forcusing is completed roughly.