List of trusted authorities - invalid?

Hello,

in the event log of several machines, I noticed entries about failed attempt
to download the lsit of trusted authorities from
http://www.download.windowsupdate.co...uthrootstl.cab .
The problem was in proxy server - I opened the port and it was then
downloaded. But while I was trying it, I actually downloaded the cab,
unpacked it, and looked at the file - certificate trust list "authroot";
when opened, it said that "this certificate trust list is not valid. The
certifiate that signed the list is not valid". Viewing the signature shows:
"The certificate is not valid for the requested usage". Should I worry?

thanks,
Vadim Rapp