From: Abder-Rahman Ali Date: 2010-09-08T00:15:34+09:00 Subject: Re: Installing ActiveRecord gem I ran the command again and got the following: C:\Users\Abder-Rahman\Desktop\Research\dicom>gem install activerecord Successfully installed tzinfo-0.3.23 Successfully installed activerecord-3.0.0 2 gems installed Installing ri documentation for tzinfo-0.3.23... Installing ri documentation for activerecord-3.0.0... ERROR: While executing gem ... (Errno::EINVAL) Invalid argument - ./