Dear Support people!

I have the following problem with Microsoft Outlook 2007:

Whenever I try to open a file with .eml extension (for example from my computer with right click, or a received email attachment), I get the following error message:

"Cannot Start Microsoft Office Outlook. The Command Line argument is not valid. Verify the switch you are using"

I have tried everything I could think about: I re-installed outlook, un-installed my previous email program (The Bat! - the .eml files were extracted from that program), I reassigned .eml file types to Outlook. I checked whether the registry is ok in this part: H_KEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Windows/CurrentVersion/App Paths/OUTLOOK.EXE (it is). If I start Outlook from anywhere else (shortcut, start menu, run command it works perfectly fine, except when I try to make it open an .eml file. I have read through the posts I found here regarding this problem and tried all the suggestions, nothing helps. I have the latest .NET framework.
The only way I can see these files is either in the Bat (which is now removed from my computer) or with a little program called : OutlookFiller, this program imports these files into outlook.

Any suggestions would be most appreciated.

My system looks like this:

Intel Pentium 4 CPU 3,2 GHz (Prescott)
Memory: 2048 MB
Video Card: Asus x1300 series
Windows XP Professional SP2
Trend Micro Internet Security
10 Mbit cable Internet