I just installed the most recent version of E17. Strange thing is that for reasons I can't understand, when I try to open system programs I begin to get "Invalid call to subprocess" messages. Weird thing is that it only effects system apps, Synaptic, Configuration apps...etc. All other apps are fine. Plus it doesn't happen all the time.
For instance -
After the initial install I ran updates via synaptic plus added a few programs and all was good. A while later (maybe 30 minutes) when I tried to open synaptic again, I got the error message.