A few hundred notices in error log..

My hostingprovider had to reboot my VDS three times today, because my (dev) site had all memory in use..
For some reason I'm getting a few hundred notices/errors (rules in the error log) per page view..

A whole lot like these:

PHP Notice: unserialize() [function.unserialize]: Error at offset 0 of 22 bytes in ... referer: ...

And a whole lot like these:

Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace., referer: ...

Because I just installed the wp super cache plugin (last page-load) that's being referred to in almost every rule.

Already tried it with the mu-plugin folder empty and with the plugins folder empty. Both didn't give the 'magic answer' (so it seems to be in WPMU itself..)??

Does anyone know what's causing it and how to fix this? I have 512mb memory at my disposal with my VDS and just the main blog and one demo blog (which I made after testing btw), so it's not like the website is being visited too much (just me, because it's still in-dev-stage).