Hmm... _ (underscores) are no problem.
Ahhh... stupid me!!!!
You found a bug!
Again... please take your favourite editor and edit /opt/lampp/lampp
At line 400 you find:
Please add a space and $2 to the end of this line. Like this:
And now try again. Now it should work perfectly.
Repute, thanks for "finding" this bug!!!