I started from scratch, deleted the program folders, deleting the program data folders. Installed SoaSE, installed impulse. It complained that entrenchment wasn't installed right. I uninstalled entrenchment (no error!), and it showed SoaSE and entrenchment seperately. Updated sins, installed entrenchment, and it let me play!
star bases are fun. Still mini-dumps once it hits 2GB of virtual memory usage, but until then it plays fine. Got my ass handed to me when I let the AI expand a bit too fast though. Fully upgraded (16k HP) starbase, a couple of L5s, and a whole bunch of frigates burned through my force of 6 capitals (all L5s) and my own 500 supply force of frigates. Killed the SB and the cap, but the horde remained. Built up again, the AI had another starbase when I went back. Got owned again. Was rebuilding when it hit 2GB. Oh well. The usage grows slowly, but it doesn't stop and it starts at 1.8GB, so it doesn't take too long.