The main reason to use CMSMS 2.x is MicroTiny. My customers campared the MicroTiny in CMSMS 1 with Notepad

I did a clean install of CMSMS 2.0.1.1 and after that a verification. Hmm, "426 files not found", but it were all language files (why report this, I did choose only 1 extra language?). Futhermore, I had to upload 2 missing icon files manually.
First impression... it looks and feels good.
I have a question: in Internet Explorer I get an error when I hit the Cancel or Submit button in Edit Content, Edit Template, or Edit Stylesheet. In Chrome I do not get this error. The error says:
got error cmsnolockexception // Could not find a lock with the specified identifiers
Note: this error is not shown in Edit Design, Edit Category, Edit Article (News).
Does anyone know what's happening here and how to solve it?
Greetz, Ronald