Unable to download files

[martpol]

Please note: I know I should have mentioned this before, but the following issue applies only to my normal browser, Mozilla. When I use Internet Explorer I am able to download as normal.

I have been running Windows XP successfully for a year, and haven't previously experienced any problems downloading files. However, two attempted downloads (one of an attachment in Hotmail and another of Real Player) recently gave the following error message:

The file /content/downloads/unknownContentType.xul cannot be found. Please check the location and try again.

I am running Norton AntiVirus and the built-in XP firewall (and have been doing so for months).

Look forward to any helpful advice! Thanks.