Before doing too much, you should take a look at http://www.linuxatemyram.com/
It might save some confusion if the label on "free" memory were changed to "memory that is currently wasted because the kernel can't find anything productive to do with it". But, that's a bit much for a column heading, so we're stuck with "free". It is completely normal for the amount of "free" memory to tend toward zero as the system runs.
Now, if this program is creating files in a tmpfs and they are not being deleted, that would indeed be a problem, and one that should be easily corrected.