Everything I can find out about this error is it is related to a bad stick of RAM. Have you tried changing out the RAM?
I also found that people with Asus motherboards have most of the problems. Is the motherboard an Asus by any chance?
There is an open file limit while transferring files over a network.
Maybe this link will give you the information to up the limits.
http://technet.microsoft.com/en-us/library/bb726965.aspx
Are you trying to access it by IP or domain name?
If it is by IP does your ISP allow inbound traffic on port 80?
It could be your ISP blocks port 80. If they do run the server on another port use some external service to forward port 80 requests. If 80 is allowed by your ISP then your DNS might not be configured correctly.
This was discussed in another thread and a solution was posted. I just can't find it now. I know it had to do with setting Windows 2008 to run scripts in 32 bit. If I find the thread I'll post a link.
Your server specs will handle the load, but, I'd add a little more ram so the server runs smoothly. I use 8gigs on my web servers and 12gigs on the database servers.
Why use Apache? Use IIS since it is native to Windows Servers.