Permissions required for a role to approve pages

Our approval process requires a compliance team member to approve all pages prior to publishing.  I setup a one-step workflow and specified that a new role I created, named "Compliance", has permission to approve.  When I login with a user assigned to the Compliance role and try to approve an item I receive the following message in an alert:
"Page Test Page: You are not allowed to modify this page: Test Page".  I am also unable to open the page by clicking its name from the back-end Pages screen.

If I change the workflow to allow the Editor role to approve and assign the Editor role to the user I have no problems approving pages.  

Why would the role I created not be able to approve while the out-of-the-box Editor role can?  Is there some set of minimal permissions that need to be granted to a role in order to approve pages?  

Hi,

If you cannot publish a page, the most probable reason for the error is that somehow the workflow service cannot function as needed. Can you make sure that you have set the WorkflowBaseURL in the ServicePaths section of the settings tab of Sitefinity? Please verify that all server / site bindings in IIS are correctly configured to point to your domain and IP address.

Please let us know if you have anymore questions.