After several days or weeks, all Xenta Servers go offline in Vista. They can't be reached via the web interface, however they can still be pinged.
Xenta 511, 527, 701, 711, 721, 731, 913
We have identified a memory allocation issue where the memory was not released properly for a Microsoft component (secur32.dll). This can be seen in the memory when the heap for this Microsoft module was re-allocated and tried to double its size after a certain time interval. The re-allocation required that a continuous block in memory was available for a successful re-allocation to be done. As a result of a failed re-allocation, all Xenta Servers went offline in TAC Vista Workstation.
If the Vista PC is running Windows 2003 Server there is solution, but older Operating Systems (like Windows 2000/XP) will likely never get this fixed. Newer Operating Systems like Server 2008/Windows 7 don't suffer from this bug.
The solution provided by Microsoft is not included in any Windows update or Service Pack release for Windows 2003 currently available. Microsoft has confirmed that this will be included in the next Service Pack release for Windows 2003; Service Pack 3. (release date is not known at this time).
2. Start a DOS prompt and go to the download folder, then type “WindowsServer2003-KB968389-x86-ENU.exe /bP2QFE” (without quotes) and hit Enter
3. Reboot PC
4. Check that you have the correct version of secur32.dll in Windows\system32. If the update has completed successfully, it should be 5.2.3790.4530 QFE