you dont say what P D A you have
I have the COMPAQ iPAQ 3900. When I get lock outs and lock ups like that I resort to a soft reset.
Do this by inserting the pointer in the small hole at the bottom right hand corner of the machine for a second or so. Just just prod it in fact. The message comes up "Synchronising your installed programs" ( Too long and it clears your machine of everything) But leaves out any new recently installed stuff.
This is all asuming you have the iPaq machine of course.
hope it's been of some help anyway.