but i found that the problem was in the result of the REST call. The result is an array with some objects inside.
The objects belong the the other application and Yii was trying to load the objects classes. I change the results only to arrays and now it works.
The other application is an internal application created with PHP without any framework. It have some webservices (SOAP and REST ) and i use CURL on Yii the make the REST calls.