Found this on their website...it sounds like maybe you've already done this, but just in case you didn't supply the info they need:
I continue to disconnect while playing. Please help!
If your connection is only poor for PokerStars or has been a long-term reoccurring connection issue it is possible it is revealing a connection stability issue that will not manifest itself on most other Internet sites and applications. We are willing to assist you in trying to isolate and resolve this issue and will require some information about your system and connection. First you may wish to learn more about disconnections and the common causes found on the Download FAQ’s
If the information here fails to assist you in isolating the cause of your disconnection, please provide us with the following information so we may help.
Among the things we will need to know are:
Operating System (i.e. Windows XP, Windows Vista, Windows 7, Mac OSX, etc…)
Computer Processor (i.e. Pentium 4, 2.4 GHz, etc…)
System RAM (i.e. 512 MB, 1 GB, 2 GB, etc…)
Connection Type (i.e. Dial-Up, Cable, DSL, Satellite, etc…)
ISP (Internet Service Provider, company name that provides your Internet service)
Router/Modem (i.e Dlink DI-624, Linksys WRTG54GS, etc…)
Please send the above details to email@example.com
Got this from http://www.pokerstars.com/poker/room/support/faq/#conn