Getting Error on gem install

[djforth]

Hi

I seem to be getting the following error when I try to install the gem -v1.1.0

ERROR: While executing gem ... (NoMethodError) undefined method `size' for nil:NilClass

I think it is being installed as a dependancy for rack-pjax, but have tried to install it on it's own with no joy

Thanks

[djforth]

Not sure if this helps but found this on stackoverflow I am on a mac but am using RVM so not sure it's the permissions issue they mention.