BleepingComputer.com: Vista File Transfer Problem

I'm trying to send files between two Vista machines in my home. Both belong to the same Workgroup and I have the exact same account name on both computers. I enabled file sharing in the Network and Sharing Center and I also told Vista which folders I wanted share on both computers. I can send files from one PC to another just fine, but when I try to send files from the other computer, I'm told the other computer is not accessible and I have a logon failure. I tried disabling my firewall but the problem persists.