When you turn on module chaching, the structure of the module changes. The PortalModuleBase loads a copy of itself from the cache into itself. The parent's ID property is set in the Skin's InjectModule method, but I've found that the child's ID property is never set (I still use DNN 3.2), so it can raise problems (for example, you can't find local resource files).
The error above comes from spmenu.js, line number 373 in my case, anyway it's the definition of SolpartMenu.prototype.GenerateSubMenus function. The script can't find a certain span, so it thinks that the version is wrong. You can alter the function to find out which span is missing. That would one of the empty spans at the beginning of the page, ending with "_divOuterTables". I suspect that the module contains a solpart menu, and while the module renders in a wrong way (due to the problem above), the menu renders wrong as well, forgetting to put the above span (among other things).
ulu