The error message indicates that the database LOG (.LDF) file is incompatible with the data (.MDF) file. I am not sure how this happened (I haven’t seen this problem for over a year), but the good news is that it should be easy to fix:
(1) Go into SQL Server Management Studio and detach the IdeaBlade Tutorials database,
(2) Uninstall DevForce
(3) Reinstall DevForce
If this doesn’t work, or you are not sure how to detach the database, get back to me.