You need to update MM:S and SM to the latest snapshots.
You must also regenerate your metamod.vdf file.
http://www.metamodsource.net/vdf
Please thank Valve for prior warning - oh right, there was none.
We will be releasing MM:S 1.8.1 and SourceMod 1.3.2 tomorrow if there are no problems. If there are, the release will be whenever everything works.
Please post bugs in the bug tracker - https://bugs.alliedmods.net/
Thanks!