Airport and network problems after recent update

I want to know if someone is aware of what went wrong with the latest OS updates, all my computers forget my local wireless connection and sometimes I'm connected to my co-workers unprotected red. Airport just won't do its job.
This issue is really frustrating since several applications like Flash for example give you and error when saving a file after reconnecting to your network after a network loss.

If someone knows how to work this around to stop this annoying behavior please advise, I'm sure I am not the only one experiencing this.
Regards