Hmmm! It probably was an error on their end - It sounds like a server error.
There have been a ton of people infected the last few days so they are probably overwhelmed right now.
Do you have your Anti-virus loaded and fully updated? You need to check for updates manually every day, or have your program do it automatically (somewhere in Options depending on which program).
If you don't have an updated antivirus program, I highly recommend AVG (FREE!! for home use) including all updates.
1. Security Test
2. Virus Scan
3. AVG AntiVirus
4. Zone Alarm
5. Search& Destroy
6. Ad-Aware