When I log into mythweb I get these errors..

Warning at /usr/share/mythtv/mythweb/includes/init.php, line 151:
unlink(image_cache/1061_20050611191000_20050611191100.nuv.png): Permission denied

Has anyone seen this before

Check the permissions on /myth/image_cache. Should be owned by mythtv with 777 permissions.

Also, if the symlink to image_cache is currently there in /usr/share/mythtv/mythweb, who owns it? Again, mine is owned by mythtv.

Apache runs as user www-data by default. Honestly I don't remember if www-data is part of the mythtv group or not when you first install KnoppMyth, but my /etc/group has an entry putting www-data in the mythtv group. However, I may have put that there when I was getting mythburn to work.

You can also try clearing out the directory image_cache, it will repopulate when you next look at the "recorded programs" page under MythWeb.