Is seomoz rogerbot only crawling the subdomains by links or as well by id?

[sauspiel]

I´m new at seomoz and just set up a first campaign. After the first crawling i got quite a few 404 errors due to deleted (spammy) forum threads. I was sure there are no links to these deleted threads so my question is weather the seomoz rogerbot is only crawling my subdomains by links or as well by ids (the forum thread ids are serially numbered from 1 to x).

If the rogerbot crawls as well serially numbered ids do i have to be concerned by the 404 error on behalf of the googlebot as well?

[RyanKent]

Roger only crawls by links.

When you are using forum software or a CMS it is very common for numerous links to be created by the software without your knowledge. If you examine your crawl reports, they will show you the URL of the page which provides the link which is generating the 404 error.