http://blogs.technet.com/b/lrobins/archive/2008/12/29/publishing-delta-crls-on-iis-7.aspxIf you have migrated or upgraded the sites on which you host your CA CRLs and delta CRLs to IIS 7, you may have noticed a (rather frustrating when you're experiencing it) new behavior. IIS 7 will, by default, reject requests containing double escape charactersen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)