Q: After installing a package with the GUI, the package isn't marked as installed ('green' coloured) in the packages list.
A: Check if you have configured the environment variables correctly. ROBOTPKG_BASE variable needs to specify the target directory of your installed software and the PATH needs to contain the $ROBOTPKG_BASE/sbin folder.
Q: Executing rosmake in an installed packages folder returns an error.
A: Check that your ROS_PACKAGE_PATH contains the folder where your packages are installed.