Also take a look at these:
PTC
https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS41551
https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS147735
https://support.ptc.com/appserver/cs/view/solution.jsp?n=CS81926
Others
http://msdn.microsoft.com/en-us/library/ms175495.aspx
http://stackoverflow.com/questions/56628/how-do-you-clear-the-sql-server-transaction-log