Crash with mechjeb 0.18.4

Hello. I am reporting a problem I have. Every time I load up KSP with mechjeb on, it either hangs on the part mumech_mechjebrad forever, and doesn't load, or it crashes after hanging with that same part.

error.log: http://pastebin.com/wGB48ztw
output_log: http://pastebin.com/TSGA4jJi
DxDiag.txt: http://pastebin.com/7FzGJPm0

I have posted this to the KSP support forum as well.