According to http://www.bioscentral.com/beepcodes/amibeep.htm#
"Memory parity error - A memory parity error has occurred in the first 64K of RAM. The RAM IC is probably bad"
Further down it also lists 2 short beeps as a generic POST failure, meaning it could be anything.
Edit, after reading the second link, it might have something to do with the HDD, but it boots into Windows normally, which suggests that it's not a fatal error.