Wacom Bonsai drivers installation may require an hotfix on XP (https://www.sandon.it/node/36)
One of my christmas presents was a Wacom Bonsai pen tablet. It was a bit disappointing to see that the driver installation got blocked in the middle. Downloaded the latest driver from Wacom site, but same result.
That's when being a programmer helps. I fired up Russinovich's Process Explorer (http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx) and found out that the installer had launched a process called RunOnce.exe - probably the main process was waiting for the child process to return, but it didn't. Just selecting "Search online" from the context menu brought me to this article in the Microsoft knowledgebase: The RunOnce.exe process may stop responding during the driver installation process on a Windows XP-based computer (http://support.microsoft.com/kb/949900). There was an hotfix available, and once requested and installed it, the Wacom driver got installed flawlessly. Hope this could help to avoid to spoil a Christmas present...