[dwm] dmenu corruption?

Hi dwm friends
I am new to the list and have been using dwm for about a month. It's a
great program. Now and then I get a strange behaviour with the command
ALT+p which is supposed to give a list of all programs and then execute
one. (I don't even know if this is what you call dmenu, but anyway it's
great and amazingly simple to use.)
Anyhow, what happens is that it won't show the programs any more, there
is just a grey bar, but it will still execute one if I type the correct
name. I have had a few computer crashes recently, and I wonder if it's
due to that. Has anyone got an idea what is happening?
Thanks, Peter

-- 
Mit freundlichen Grüssen
P. Vollmar
Dipl. Übersetzer HDS
VOLLMAR ÜBERSETZUNGS-SERVICE
CH-9248 BICHWIL, SWITZERLAND
Tel/Fax:   +41 071 952'77'45
Homepage: www.vollmar.ch
Aktuell:  www.vollmar.ch/download
Computer: www.vollmar.ch/linux