Well the problem is its not able to locate the class file for DeferredFileOutputStream. You need to check if you have commons-io-1.1.jar and commons-fileupload-1.1.jar files in the WB-INF\lib folder. If the problem persists try putting the same in tomcat lib folder as well.
This is due to a missing dependency of commons-fileupload.
Between TC 5.5.25 and 5.5.26 commons-fileupload has been updated from version 1.0 to 1.2. commons-fileupload unbundled some commons-io classes between 1.0 and 1.1, so we need to bundle commons-io with the manager webapp.
Problem can be fixed by including commons-io version 1.4 in the manager webapp."