Anti Splog can not activate new version due to "Fatal Error"

Hello,

I am upgrading my sites.

I've just uploaded the latest anti-splog plugin and deleted the old version from my mu directory. I've also moved the necessary file to wp-content.

I am unable to network activate and am getting this error:

Anti Splog can not activate new version due to Fatal Error

Thanks in advance for your guidance.
Ralf