WEBrick fails after upgrade to 0.14.4 (WinXP)

I noticed that all the script files were updated to #!/usr/bin/env
ruby which obviously breaks on Windows. But even after changing them
back, WEBrick simply won’t start. I get the following:

C:[projectpath]>ruby script/server
=> Booting WEBrick…


It says “booting…” but then just stops. Is there a log I can look at
to find out what’s going on?