Error using Ant and nested "file" resource parameter

Hi, I’m having an issue using an rpm task that has a nested “file” parameter like:

tarfileset(prefix: '/usr/share') {
            gzipresource() {
                file(file: 'files/apache-tomcat-7.0.47.tar.gz')

when i execute the build I get the error

Converting class java.util.LinkedHashMap to File using toString() method has been deprecated and is scheduled to be removed in Gradle 2.0. Please use, java.lang.String,, or instead.
:buildRpm FAILED


Execution failed for task ':buildRpm'.
> no resource specified

It looks to me like gradle is interpreting the “file” element as “Project.file()”. I feel like I must be missing something relatively simple but can’t seem to find my answer by searching.

Thanks, Charlie