When installing a trac one-click setup package on Dreamhost, you might encounter the error “Missing or invalid form token. Do you have cookies enabled?”. This isn’t an error that is limited to Dreamhost installations, as I have seen it crop up a bit everywhere.
When looking in the .htaccess file that controls your trac install (in the trac directory itself normally), you can find some rules like this:
RewriteCond $1 !^(.*).css$
RewriteCond $1 !^(.*).gif$
RewriteCond $1 !^(.*).js$
That should take care of the problem.
The solution was mentioned on the trac site.