>Yes Al, I've tried without luck :-(
>
>The problem is that the parameters can contain spaces en the temp names, so thats why the need of double quotes.
>For example: "c:\documents and settings\user\filexx-12345-fddefdsf-23123c4.tmp"

I use parameters in several scenarios, and it always works... it's possible though that the command line (cmd.exe) has some limitations to the length of the command line.

You may try to put those parameters into a text file, and issue a

tst.exe <params.txt

i.e. have the parameters come from the text file. Try to find whether there's a limitation to cmd.exe first.