Portal running on VMware/win2k3/MSSQL that goes down with 4 users logged on

Hi

We have a portal running on VMware/win2k3/MSSQL that goes down with 4 users logged on.

We get a "SAPWebAS Engine is starting.......Dispatcher running but no server connected" error with very few users doing regular work.

At first it happened with only 1 user logged on. After this we boosted RAM to 16 GB (SAP says 4 GB is enough for 100 users). After this we still get the error, but the users can work for some time.

Its a bit strange, I cannot see anything regarding this in the logs/dev traces. However there is entries in the event viewer. Event Id: 35712. Description: SAP-Basis System: Operating system call recv failed (error no. 10054). After this we manually have to restart the portal.

We suspect it might be the VMware or Java VM, but is in doubt wich way we should direct the further investigation. Have any experienced similar and what was the problem then?

Regards

Kim