First if you pressed any options on the phone for "customer service" and not "technical support" hang up and press the buttons for technical support or you will be on hold till they close tonight customer service is horrific at best. There was a note from their VP on here awhile back, it's not on the Adobe website anymore but Macworld UK has it archived ( http://www.macworld.co.uk/blogs/index.cfm?blogid=12&entryid=806 ). I guess the situation still has not been resolved.
Second, if the installation got corrupted try the Clean Tool (http://www.adobe.com/support/contact/cs4clean.html )and then try installing again. That's the only suggestion users here will be able to give. Anything more you need Adobe.
I got through to Adobe, they walked me through a few simple things that I had already tried (copy files to the HD and install from there, download a trial version) nothing seemed to work. Then there was more searching for a solution, then . . . nothing. I was still connected, but no one on the other end of the phone! I stayed on for 10 minutes asking if someone was there and nothing. FRUSTRATING
I downloaded the Clean Tool, but since I only purchased DW C4 and not the suite, there wasn't anything to remove.
I'm thinking about installing OX Snow Leopard to see if that helps.