Hi everyone,
I was experiencing the exact same problem as
delmax with my Dell Axim 50v. I decide to try out the "knife solution" and amazingly it worked!
I simple pried off the switch's cover and removed all the contents of the switch box. Now my PDA cannot be locked anymore but that is OK with me.
I attached a picture of the switch all taken apart. I'm pointing to the switch box with my screwdriver.
I'm so glad I found this forum. :-)