The palette buttons are calling a handler placed in the main stack and returning "can't find handler" error.
Hmmm.
Because you copied buttons from one stack into another, that does not mean that those buttons can access handlers in the source stack. The message hierarchy is rigid. A button that lives in a stack might pass messages along the hierarchy starting from that button, that is, to the objects above that button, groups, card, stack, and farther...
But placing such a button in another stack puts it in a different message path hierarchy, and that will not include that original source stack.
There are many ways to fix this, but I would need just a little more information about the handlers in those buttons to be able to direct you best. For example, I assume that the buttons in question sent, say, a "mouseUp" message to a handler in the stack script. is something like this the case? If so, do you see what I meant above?
Craig