Its a bug, already fixed in whatever our next fix pack or release is. Cheesy workaround - rename your gadget package from SomeLongGadgetName.gadget to SomethingShorter.gadget.
I've added it as Bug#20 to the known bugs list. I'm sure I can find some more before the week is out.
There's two more to go up, once I've done Repros for them! Namely, "<g:text> quality" and "Gadget never shows on sidebar if it's updated too frequently"