Cannot access Spywareblaster update site

I am running Spywareblaster on two computers A and B that are connected in a LAN. Until recently I had no problem to update SB on either computer.
Now the update on computer A works still fine while on computer B I get the message that the file http://www.spywareblaster.net/sbversion2.txt cannot be found. Checking for the reason I found out that from this computer I cannot access the site "http://www.spywareblaster.net" correctly.

While on computer "A" I get a redirection to the javacoolsoftware site, from computer "B" I only get a message that tells me that the server uses Apache server software but has no content yet. Cannot access any other file to download manually either.

I suspect that this is a Firewall problem, but I have no idea why this has come up now and how to resolve it.

I am running Windows XP Home with the MS Firewall active on both computers.
I also run Symantec Antivirus with the Norton Personal Firewall disabled on both.

Can anybody help?