Remote Dektop Dilemma

I have a issue that is driving me crazy. I have a WDT3250 handheld scanner device that is using WinCE 6. I am trying to use the remote desktop to connect to a desktop computer. My problem is that whenever I try to connect to the computer via remote desktop, I get the remote computer can not be found message.
Here is how things are set up:
WDT3520 scanner with 802.11g wireless built in. It is connecting to the DHCP router (Sonicwall TX100) and getting a LAN IP address, and it is connecting to the internet via the router.
Windows 7 Pro desktop computer on the LAN, connected to the same router on the same subnet, everything working on it (internet, ip address, etc). Firewall is opened up to remote desktop (heck, I even turned the darn thing off, just to make sure). The correct users are configured for RDP which is also enabled.
I have connected to the windows 7 desktop PC using RDP (remote desktop) from another computer on the LAN, so I know that is working properly.
I am able to ping the desktop from the scanner, so I know it can find it on the network. I am trying to connect using the ip address, but I have tried using the computer name as well, but to no avail.
I took the scanner home, and after messing with it for several hours, I finally got it to connect to my home computer via RDP, so I know it can do it. I took it back to the office, but still the same problem. When I click on the connect button, it asks for a user name and password. When I give it that information, it quickly gives the "can't be found" message.
Does anyone have any experience connecting to a remote desktop via WinCE 6 that could help me out with this problem?

On the 7 machines RD settings (system in control panel) are you using NLA or not? (more or less secure option)

I am using the least secure option.

Do you know what encryption level it is set to?

Where would I find that? And thanks for your replies.

Before I send you off on a wild goose chase, have a look through the Windows security logs on the PC as well as the system and app logs. When you attempt to log-in it will proably write something either a security error or a state error.

Nothing in the logs on the PC. It's like the remote desktop client on the handheld is never even finding the PC.

Start > Control Panel > Administrative Tools > Local Security Policy

Security Settings > Local Policies > Audit Policy

Set 'Audit account logon events' to success & failure
Similarly 'Audit logon events'

Security Settings > Advanced Audit Policy Configuration > System Audit Policies - Local Group Policy Object
Ensure that the account logon and logon / logoff settings are enabled for success / failure or are not configured

Then try again and see if anything gets logged this time