I'm currently experiencing similar difficulties with both FW and Phex. I have both set to 1 download, so I don't think that's the problem. There have been no significant system changes either.

While I am not sure yet what it is, I don't think it has to do with either Phex or FW. What I have done thusfar is uninstall/reinstall the JRE, and both worked ok this time, but time will tell...