I just downloaded the latest version of Python (0.99.84) since global variables couldn't be accessed directly in Python with 0.99.82. Pumped and all, I ran a little test to see if it works fine with a 'Number' global variable and it worked perfectly. Delighted, I assign a python variable to a 'Text' global variable and tested it out, expecting fireworks. All I got was a crappy runtime error...
Before I decide to post it on the bug tracker, I've replicated the bug and posted the *.cap file below to make sure it's not a problem with my laptop or anything.
Also, try changing the global variable to 'Number' and assign it a number; should run fine with the number being displayed at runtime.