NetBeans 6.8 doesn't detect installed Rails on Ubuntu

I use Netbeans 6.8 with Ror. If i click "AutoDetect Platforms" , IDE detect Ruby 1.8.7 (2009-06-12 patchlevel 174) [i486-linux], but when 开发者_高级运维i try to create RoR project, it says that Ror not detected.What could be wrong?

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Ruby != RoR.

Are you sure you have Rails installed on the machine? If not, try running gem update rails and making sure you have it installed.