@michaelbuckner To clarify you used our installer which ship with its own JRE? Other questions is 32vs64 bit win7? Did you run time CMD? I test with win7 64bit ultimate but I usually test without jre because I have multiple jvm's installed on my windows machine.

I tried both.

Initially I had JRE 1.8. I removed that + jruby and did the 64bit installer with bundled JRE.

Time/timezone on my machine are correct.

Ok, I need a backtrace from this and an example session with commands you ran, as you ran them.

To get a backtrace, I think the gem command has a --trace or --verbose or something. Also get a trace passing -Xbacktrace.style=raw to JRuby, to get the full Java trace in case it is being Rubyfied.

Really can't do much until we get the full backtrace, since it works ok for me here.

there is very similar looking issue here: jruby/jruby-maven-plugins#65
both using jdk1.8 but can not reproduce it either

I just confirmed gem install is working on Windows after making a few updated fixes. Please confirm with pre2.