What do you mean by "Error: Unable to Load Font"? That's not an error message from Processing. Do you have an error, a stack trace, something?

I think it depends on the memory available, the size of the fonts (size of char set) and perhaps some other factors.
Depending on your needs, using createFont to use a system font might be lighter.

When I try to load it just has trouble finding the .vlw file despite it being in the data folder. That makes a lot of sense though that it would be a variable amount dependent on the computer being used. Would be cool to have a processing tool that kind of gauged memory usage.