Here's how I get it to work. I get no FC's. And it works smooth for me.
I flash 20110618-signed something or other. I do not edit it. I do not remove market updater...nothing.
A window pops up after signing in to install more apps. I press cancel. Finish signing in. After this is complete I open market and it's updated to v3.1.5

The 20110618 I asume is the gapps you used, I can't find that one so I tried 20110613 from rom manager and followed how you did it but the end result was the same...and I did another fresh clean install of thr whole ROM using the 0613 version of gapps.
I can use the browser to go to the market and download with no problems at all, it's just the app that is driving me crazy lol...

@Jethro650 I suggest you do a backup, then a wipe data/factory reset. From there try again. Maybe something had gone wrong along the way and flashing over is not fixing it. And yes you're right, it's 20110613 Universal that I use.

Lmao guess it will have to wait till after work...battery already under 50% from wiping and flashing and don't want to flash that way. But I will clean house tonight including sd card just to be sure and do another fresh clean install just to see, if that don't work I might try using DoubleOEK's sbf and go back to stock 2.1 and give it a really fresh start...damn been so long since I rooted lol will have to look up the instructions again...

Sorry about all the hassle. It's just that it's not happening to everyone only a handful. That leads me to believe the problem is in the device setup. Keep me posted.

No need for the sorry lol...I know it's something with my phone or it's set up...just frustrating thats all. I would like to figure it out though because like you said there are a handful of people going through this.
One more thing I can try that I found googleing last night is that some people have solved this (on different phones with different ROMs) by disassociating thier credit card from thier google account...I canMt seem to figure out how to do that short of creating a new account and I would rather not do that unless I have no choice....has anyone done this before?

Im also gettin dis same problem an i cant access d market apps.
D only ting left to try is using an Older Nightly an see if it works...

@ngiordano not sure if this makes sense but here is what I did. I figured out how to delete my credit card info from my market account, cleared cache and data via the settings, manage applications on phone. That didn't work, still the server error on the old market and force close on the new market. So then I started getting ready to completely wipe the phone and start over, I copied my sd card contents to my computer and then unmounted and erased my sd card from the phone menu. Just for shits and giggles I tried the market...well, I have now reinstalled root explorer from market and updated superuser from market and reinstalled launcher pro from market,,,so far no force closes on the new market. The market was very slow and laggy when it first opened but as a little time has passed it is getting faster and feels more stable, app descriptions are opening faster and scrolling it smooth now. Just reinstalled tapatalk as I type this.

I had a felling that was it. Not sure why this happens to some people. I have not deleted anything off my card and was able to transition from one build to the other just fine. I'm guessing it may be something in the android folder. That stores app data as well as the .androidsecure directory. However it is not deleted because it stores save data.

Well, guess I spoke too soon. Installed a few more apps then took a break to eat supper and when I opened market right back to the force closes, so I started uninstalling things in the order I installed them to no avail. Now I am right back where I started. I even tried actually formating the sd card instead of just erasing it but no luck, 

Same problem here, i preffer to use the web market to get backto the others roms, this one is so great.

I'm not giving up...well maybe for tonight lol. Still a lot to try but 4 am and a 12 hour shift starts very soon and I need some sleep.

@ngiordano think I got it this time, sooooo simple lmao, after some sleep I did another search with this mornings coffee and found on the cyanogenmod forums a few threads....

Wow that's ridiculous!

It sure is but it seems to be working lol. I had it working last night for a bit but soon as I closed it to eat supper it wouldn't open again. After changing the language (I had it set to english canada I think it was) I've had it opened and closed probably 20 times so far this morning with no issues yet.
The biggest problem I see is what if this is happening to someone who can't read english wtf are they supposed to do....
BTW--> I am on nightly 126 with the newest gapps rom mamager has to offer...

It may be just an English language bug. Good find

Rofl yeah if those posts are correct it must be difficult to translate between canadian english and american english.....eh

I changed d language to English united states an market 3.1.5 no works without FCs thanks ;D

Well it's been about 15 hours now and everytime I pick up the phone I opened the market just to see and it has worked every time. Guess this issue is solved in my case at least.