Thanks Jeffrey. These are the instructions I used for my initial installation, and I just did a new installation in case I'd missed a step or something. Unfortunately, I'm still getting the same error message.
When I ran the last command of the GTKDatabox installation (sudo make install), I got a bunch of warnings about a deprecated pre-processor symbol. I'm not very familiar with the C/C++ language, but I'm wondering if there could be an issue with the versions of everything I'm using being compatible. I haven't found any sort of list about version compatibility-- if that's a reasonable guess, is there a list somewhere that you know of? Or, do you have any other idea what my problem could be? Thanks.