Huge spike in 404s and 500 erros

[SystemIDBarcodes]

I'm curious what might cause an inordinate amount of 404s in the reporting from SEOMoz's dashboard.

I'm exploring links that are marked as 404s and they are (for the most part) working. I talked with the sysadmin and there were no outages this weekend. We also had a number of 500 errors reported in Webmaster Tools but everything seems to be up.

Any ideas?

[AdamThompson]

If SEOmoz and Google Webmaster Tools are both reporting errors, I would guess there actually was a problem with your site.

[SystemIDBarcodes]

The interesting thing is that SEOMoz threw a bunch of 404s that, overall, are not 404s whereas Webmaster Tools is showing discontinued products which makes sense. We didn't see any outages this weekend so I'm a bit confused.

[AdamThompson]

Maybe submit a support ticket to SEOmoz to see if the 404's might have been false positives.