Mmc.exe Access Denied Error 5 for services.msc

I'm trying to use MMC at home using Windows 7 to connect to services.msc on the office computer to no avail.

User with full admin/owner rights on the Home computer
User with full admin/owner rights on the Office computer
Computer name for home computer is Home-computer
Computer name for office computer is Office-computer
Home computer is running on Windows 7 Ultimate SP1
Office computer is running on Windows XP Pro SP3
Home computer is using a router and is a part of the WORKGROUP Workgroup
Office computer is using a router and switch and is a part of the WORKGROUP Workgroup
I can ping the external (isp) ip address of the Home computer using the Office computer
I can ping the external (isp) ip address of the Office computer using the Home computer
IP address of home computer has the same parameters (?) as the office computer
Added Home computer user name by inputting the object name xxx.xxx.xx.xxx\ComputerNameto the Office computer asks for password; inputted user with full admin rights username and password indicates that the object was not found

Added Home computer user name by inputting the object name xxx.xxx.xx.xxx\Username to the Office computer; asks for password; inputted user with full admin rights username and password and indicates that the object was not found

Home and Office ISP supplied IP addresses are static.

All computers at work and at home have static ip addresses

Both home and office routers have dhcp assigned

Office router has port 1723 for PPTP forwarded

Office router has port 500 for IPSEC forwarded

Tried forwarding port 50-51 for IPSEC as well

Tried forwarding port 135 just because I found it on the web. It did not work.

Port forwarded all of the above ports. Failed.

Using IP Address as the Domain

Tried using a computer name as a Domain too and failed

Used a VPN. All computers on the Office side can be seen at Home but all services.msc, etc. still have the access denied error



On the Office side, I get this a dialogue box that asks for a username and password:
http://imageshack.us/photo/my-images/848/officeenternetworkpassw.jpg/

After I input the correct user name and password I get this:
http://imageshack.us/photo/my-images/827/helpnamenotfoundoffice.jpg/

Tried the Domain\user, the user@Domain as well as \\ip-address.

For both sides when I click on Check Names I get a WORKGROUP\IP ADDRESS which simply results in an Error 5 Access Denied when I click on services.msc
http://imageshack.us/photo/my-images/152/helpchecknamesselectcom.jpg/

A dialogue box appears on the Home side which has the same result as the Office side:
http://imageshack.us/photo/my-images/254/helpenternetworkpasswor.jpg/

All the pictures are from imageshack so you have to open link the images.

I've been working on this for 2 days now but I still can't seem to find a solution.

Please help.