I got that error when I opened up our beautiful migrated production environment. First thing I tested was to check if every site had the error.. weird thing was that only a couple of sites had that error. So (obviously) I ran the error in Google and found the following blogpost : Forefront Security and MOSS ( Exception from HRESULT: 0x80041050) by MOSS Paradox which give me the source of the problem and the solution :) It seems that ForeFront (the new (and only) antivirus tool for SharePoint 2007) didn't like some of the files that were in our environment and instead of displaying a nice and userfriendly error that a "Virus was found, so therefore access to the site is blocked" we get the "Exception from .." error.
Fortunatly there were no viruses, so we changed the configuration of ForeFront to be less restrictive. Enabled only three virusscanners instead of five and changed the bias settings to 'max perfomance'.
Also before I googled for the solution I found that opening the central administration page took ages! No matter how many browsers I let connect to the admin page none of them could get access. Until I did an IISRESET and then before the service was stopped, the central admin page opened. So I checked out the eventviewer and found that ForeFront was reporting errors like "SharePoint Realtime scan exceeded the allowed scan time limit" and "Scan/Clean document <filename> failed due to timeout error". Then I tried to stop the ForeFront services and they couldn't be stopped in a timely order fashion. After the services had stopped, the central administration page was accessible again. Then I went into the configuration page of ForeFront and there I unchecked the option that the 'SharePoint Realtime scan job' scans documents on download. '
By doing this configuration and mostly due to unchecking 'scan documents on download', our environment was suddenly a lot faster as it were using the default ForeFront configuration.