I'm probably a bit late to the party, but I wrote the junitcategorizer for my thesis project at TOPdesk. Earlier versions indeed used a company internal Parent POM. So your problems are caused by the Parent POM not being resolvable, since it is not available to the outside world.
You can either:
<parent>
block, but then have to configure the Surefire, Compiler and other plugins yourself<parent>
<groupId>com.topdesk</groupId>
<artifactId>open-source-parent</artifactId>
<version>1.2.0</version>
</parent>