Default "Insufficient Storage" error when installing apps

Hi all, I've recently installed This ROM by michaelm_007, but every time I try to install or update apps I get an "Insufficient Storage Available" error even though I have 167MB of free internal space and lots of SD card partition space available.

I Have CM7r2 HBOOT so I suspect it has something to do with the cache size, but I tried both of the fixes on this page but the first one errored out and the second one did nothing.

Can anyone offer any assistance?