Minor Description
The Reports page (under 'Manage' on the menu at the left of the screen) seems to show any missing dependency using the error icon.
On my computer this results in lots of errors showing up, because optional dependencies have not been downloaded.
I would suggest that the code generating the report should check if a dependency is optional, and if so tag it as a warning or an info, and not as an error.
For example, ant:ant:1.6.2 has optional dependencies on xerces:xerces-impl:2.6.2 and xml-apis:xml-apis:2.6.2.
In ant's pom file, these dependencies are tagged using: "<optional>true</optional>"