Note: I read the answer by scoop, but then looked at the specs for the x30. It seems to indicate that the x30 uses ultranav. I have a t61p, and the below works with my ultranav. Worth a try:
Go to Control Panel, Mouse, and click on the UltraNav tab (it may be labeled TrackPoint instead).
In the TrackPoint section, click on the Settings button.
This will bring up the TrackPoint Properties screen.
In the "Choose Scrolling or Magnifying Glass Function" section, pick the Neither option.
Neither probably should be labeled "Middle Mouse Click", but it's not.
I personally use the scroll feature, which is the default. It takes a couple days to get used to it, but it provides better control over scrolling than the trackpad. To use it, click and hold it with your thumb (your cursor will change to scroll bars), then use your index finger on the trackpoint to scroll up/down. After a couple days your thumb will naturally find the 'lip' of the middle button.
I know this probably isn't what you want to hear, but from what I can tell there is no fix for this, just a lot of upset Thinkpad & VMWare users:
VMWare Communities
VMWare Communities 2
I think the problem is that the VM Ware window is capturing the mouse event, and not doing anything with it. A possible solution might be if there is a driver for the trackpoint that you could download and install, you might be able to get it working in the guest OS.
Best Answer
Here is a work around just posted using Autohotkey to simulate a scroll wheel while holding down middle click after a certain amount of time:
http://forum.notebookreview.com/threads/ultranav-middle-click-button-scroll.423415/