Adding PATH's to all machines is very painful
Instead write a temporary batch file with:
cd\<whatever directory its in>
<whatever program it is>
And then @command([Execute]) that batch file.
Assuming of course that the clients virus scanners will allow you to do that.
On the bright side, its the target applications fault for assuming that it'll load from the path or the current directory. Any programmer worth his salt would have stuffed a whole load of registry lookups in there and dynamically loaded the DLL's from the right place.
I can imagine that last statements a whole lot of comfort right now.