Perhaps this Glitterball was overheated a while ago. They will overheat fast and the wax will just sit there and try to flow. How is it on the heat coil is all of the wax covering it.
Glitterballs run great with a 30w even though a 40w maybe recomended. The 30w will have this lamp live longer. As for the flow make sure there is a coil if not install a small coil and see what happens. Perhaps this vase was overheated with many years of use with a 40w bulb.