BASIC runtime error: object variable not set

Hi,

I'm a contributor to the maven-ooo-plugin (https://github.com/fredericmorin/maven-ooo-plugin). We use this plugin for a project where we want to migrate from Ant to Maven. But for the OOo plugin generated by the maven-ooo-plugin I got a "BASIC-Laufzeitfehler. Objektvariable nicht belegt" (in English probably: "BASIC runtime error. Object variable not set") when I start OpenOffice. The registration ('unopkg add -v myplugin.oxt') itself was successful.

Any ideas what could be wrong with the generated plugin? Or where I can look for the cause of this error?

regards,
Oliver