.htaccess error causing error 500

[just_bruce]

I have xampp on an external usb drive. i plug it in and take it out often.
the first time i start up it works fine, but after that i can't get the startup screen, getting an error 500 screen. when I checked the error log, i discovered that the .htaccess file in xampp\security\htdocs was corrupted; there were TWO drive letters 'F:F:\...' in the string.
I am wondering what is putting them there, and how to prevent it? It seems that everything is ok at first. I fixed the problem by editing the file, but i believe it reoccurs under some circumstances.
Anyone have an idea? I have had the problem with a stick as well as a big drive on usb.
This is on windows 2000, and the xampp 1.6.7 was simply installed with no quirks.
thanks for your help.
bruce