Freezing/beachballing/lockups when using foreign wifi

Question

Like my new Air it's pretty stable accept for one phenonmenon when I get on outside wifi networks. It goes like this:
-Get on open wifi network from somewhere work a little bit.
-Close macbook and packup.
-keep macbook closed long enough for standby to kick in (70 minutes)
-Return home and open up macbook air.
Internet connection refuses to work. Launching apps will trigger beachballs, quitting apps will trigger beachballs (sometimes on certain apps, sometimes on all of them). Hard to logout or restart because locked up apps are blocking the process. Sometimes I can succesfully log out and restart the system, which will fix the problem. Sometimes I am not as lucky and I have to force shutdown.
It's difficult for me to recreate the issue since I have to go out to do that. I have resetted the SMC, I can't tell if that will help.  I'm sure it is related to connecting to outside wifi networks because this is the only general condition when this will happen. I hope I don't have to constantly do restarts and SMC resets to keep this from happening. My mid 2007 iMac was never this flakey.
Has anyone had a similar problem?

Answer 1

Just a follow up...
I was never able to get to the specific cause of the problem. I reformatted and the problem never came back. The only difference was that I restored my system by manually copying off my backup rather than using Migration Assistant. (MA)
That was the first time I had used MA and I had told MA to only copy home folder/user files from the old system in hopes of minimizing potential issues. I can only conclude that MA had caused an issue with the installation.