Boot Scan

Every time I do a scheduled boot scan (see report below) these three files come up with an error number. Why and what do I do to correct the problem?
Please keep in mind I know every little about computers when giving the solution.
But thanks to AVAST Forum I am learning.

04/28/2009 09:13
Scan of all local drives

Number of searched folders: 4290
Number of tested files: 57686
Number of infected files: 0


05/28/2009 11:48
Scan of all local drives

File C:\WINDOWS\SoftwareDistribution\Download\1741e6217a93d36aaaaa3cead0913a10\BIT18.tmp_sfx_0046._p Error 42127 {CAB archive is corrupted.}
File C:\WINDOWS\SoftwareDistribution\Download\73a2b837fd570c01cee685772aade693\BIT20C.tmp\mrt.exe Error 42127 {CAB archive is corrupted.}
File C:\WINDOWS\SoftwareDistribution\Download\fb0d0ed5e5e0d3e7ce20db4d65bad679\BIT41.tmp\mrt.exe Error 42127 {CAB archive is corrupted.}
Number of searched folders: 3951
Number of tested files: 221667
Number of infected files: 0


Thanking you ahead in this matter,

“Microsoft Malicious Software Removal Tool – MRT.EXE”
The file indicated by you is a bad download. As far as I can tell, it’s crapp and should be deleted but wait for a second opinion.

Thanks Bob. Will do.

Yes, come up early in the bootscan.
You may have canceled during a download at some time.
Not a big deal. Can locate and delete if you want.

Thanks.