May,
I'm guessing that the Deployment Unit for your solution is not Customer Relationship Management. To be able to write to standard SAP Objects, your solution needs to match the Deployment Unit of the Object you're trying to write to.
There is a [DeploymentUnit (...)] annotation for Business Objects, which you may want to look into if you have a solution in one DeploymentUnit and need to write to an Object in another - i'm not 100% sure what the restrictions are for it.