In the future, please file a separate ticket for each issue instead of combining multiple issues into a single ticket. That makes it easier to track the solutions of the individual issues.
The error message you showed above says that MacPorts failed to install BWToolkit, as a dependency of MongoExplorer. As you see from the error message, BWToolkit only works on OS X 10.5 and 10.6, not earlier nor later versions; it is not within our realm of responsibility to fix that. On those systems, BWToolkit and MongoExplorer should install fine. If you require support for this software on other versions of OS X, you'll have to take that up with the developers of the software.
If you're not able to build MongoHub, please attach a main.log file showing the failure. I realize MongoHub in MacPorts is outdated, but the developer of MongoHub had originally made it very difficult to build his software; the version I added to MacPorts in February 2015, 2.7b10, was the latest version I was able to build at the time. I attempted to work with the developer to resolve this so that we could update MongoHub in MacPorts to a newer version, but last I checked, I was still not able to build it. However, it has been over 7 months since I last checked.