Okay, did you check out the MTU as described in the linked thread?
"Lost network connection" can, at times, actually mean just that, a problem with the network connection (network card, router, cabling) anywhere in the chain from your computer all the way back to the Web site. Is there any sort of support Web site at your ISP where you can check for trouble reports? Also, do you have any new networking hardware (especially, but not necessarily, wireless) at your end? Anything at all that may have changed can be suspect.
You can rule out a lot of possible problems by trying a different browser (Camino, Firefox, etc.). That will at least tell you if Safari or something else is at the root of the problem.