I was once launching the Dynamics AX DB Upgrade Preparation Tool (AxDbUpgrade.exe) on a Windows Server 2008. I was using the version distributed with the Dynamics AX 2009 DVD. The issue here was that the tool was crashing shortly after launching.
In the Application event log I could find the following error:
The reason for this issue was that the Microsoft SQL Server Native Client for Microsoft SQL Server 2005 was not installed on the machine where I executed the tool, and installing it solved the issue.