after successful RC1 install other services fail

I have a windows service which runs on the local system account and
creates a system-wide drive mapping using the subst command. This works fine with IE6 installed. Upon
installing IE RC1 (the same thinghappens in beta 3) my service dies with the following error logged to the
Application log

Service cannot be started. System.ComponentModel.Win32Exception: Access is denied
at System.Diagnostics.Process.StartWithShellExecuteEx

I get the same behavior on WIndowsXP SP2 and Server 2003 SP1

[530 byte] By [MarcIERC1] at [2007-12-25]