I'm have DW CS5.5 with your extensions Data Assist 2.10, Design Extender 1.1.1, Universal Email 4.0.1, eCart 5.06, Security Assist 1.1.9 installed and enabled.
Every time I start DW I'm getting the error "At line 22 of file "<path-to-config>:Floaters:WA_SiteTools_ProgressV2.js": theDOM has no properties"
I've completed the same old routine... uninstalled everything, empty the cache, reinstall everything and the error persists.
I agree with Andrew Dodd. I think that these combined extensions are not a good idea. I've brought just about every extension over the years. Each year they seem to get more and more bloated. So much so I've been weening myself off your extensions and doing hand code because it's faster to do the hand code in the long run. I'm really getting tired of fighting with them.