just looked at this a little bit closer and this is what i have found out. KDE ships with two application launchers, application launcher and application launcher menu. PClinuxos uses application launcher menu and this does not allow icons to be dropped on the desktop from the menu but application launcher does.
I use application launcher and it works here and i just assume it also works in application launcher(my bad)
You can temporarily add the application launcher and then drag the icons you want and then remove it as a workaround while waiting for a solution.
i meant locking and unlocking of the widget, i just tested it again and icons on the traditional menu(pclinuxos default) can not be dragged and dropped on the desktop but icons on the
yes, the desktop can be locked but i meant locked widget in this case, bad use of terminologies on my part ..
Almost forgot ........ have you some info on this?
I don't understand what it is that is being locked ...... or how.
Any info appreciated 
if you have kickoff menu(application launcher), you can click the menu, then go to "leave" icon and it will show its contents, the "session" section has three icons, logout, lock and switch user. Click "lock" and the desktop will lock and turn totally black demanding a user password to unlock it. This is "locking the desktop", the other one is "locking the widgets" since the desktop is usable but the widgets cant be moved.
the default traditional menu has this option too, just click the menu icon->leave->lock screen