Hello.

Our plans have developers are all in the user group "developer". For each of our plans, in the permissions, we have the group "developer" assigned "view" and "build" rights.

They all can see the choice to enable or disable a plan in the dropdown, as per the doc:
http://confluence.atlassian.com/display/BAMBOO/Granting+Plan+Permissions+to+Users+or+Groups

However, if they click on it, they get a "Access Denied
Sorry, you have insufficient permissions to view the page. Please contact an administrator if you believe this is an error.

Go to...
Site Homepage " page.

In the log it prints out something along the lines of:
2009-07-23 17:26:50,467 WARN [btpool0-2] [AuthorizationLoggerListener] Authorization failed: org.acegisecurity.AccessDeniedException: Access is denied; authenticated principal: org.acegisecurity.adapters.PrincipalAcegiUserToken@d39be46a: Username: com.atlassian.bamboo.user.DefaultBambooUser@9786e65a; Password: [PROTECTED]; Authenticated:true; Details: null; Granted Authorities: ROLE_USER; secure object: ReflectiveMethodInvocation: public abstract void com.atlassian.bamboo.build.BuildManager.saveBuild(com.atlassian.bamboo.build.Build); target is of class [com.atlassian.bamboo.build.HibernateBuildManager]; configuration attributes: [ACL_BUILD_EDIT]