undefined method `find_by_contents’ ,acts_as_ferret

When trying to use the acts_as_ferret plugin in a search page by using the find_by_contents method then the following error appears:

It seems that the API of the plugin has changed, and the

method should be replaced with the:


ERROR: While executing gem … (ArgumentError)

After a recent upgrade to a newer rails version the gem package manager seems to be broken. Everytime you try to use gem install gem_name, you get the following error:

Deleting the cached files as suggested in other posts results in the error:

As suggested here, you need to do:

which should be updating the gem version to the latest one, ie 1.3.0

FBML Error (line 5): illegal tag “body” under “fb:canvas”

When trying to use facebooker according to the Developing facebook platform applications with rails book, in the network_test step you are getting the following error:

It should be caused because you are using the facebooker gem instead of the plugin.
Install the plugin: