Habe mal auf die Schnelle folgendes dazu gefunden:
Anyway:
This seems to be specific to Windows2000 .
Some versions of the SAPgui attempt to use the new QoS feature of the TCP/IP
stack in Windows2000,
but it does not always work as expected -
the OSS-notes say it is a Microsoft bug.
You can disable this:
go to the control panel "system", tab "advanced", button "environment
variables" and add a variable called "QOSDISABLE"; it can be a system
variable or a user variable - it does not matter - and it can have any
variable you like (on my PC it says "for SAPgui").
Leider nur englisch aber ich denke es sollte doch verständlich sein.
Probiert mal o.g. aus, ich werde aber weitersuchen!