Error using exec-maven-plugin inside of iterator-maven-plugin - maven

Question

We are currently using the exec-maven-plugin to import oracle .dmp files into a database. Our list of .dmp files keeps growing so I wanted to try using the iterator-maven-plugin to loop through a list of .dmp file names. when I wrap the iterator plugin around the exec plugin, I receive a java error about being unable to find 'executable' in class java.lang.Object. I'm not strong in Java but it looks like the iterator plugin is blocking the exec plugin from working correctly.
<build>
<plugins>
<plugin>
<groupId>com.soebes.maven.plugins</groupId>
<artifactId>iterator-maven-plugin</artifactId>
<version>0.5.1</version>
<executions>
<execution>
<id>import-dmp</id>
<phase>install</phase>
<goals>
<goal>iterator</goal>
</goals>
<configuration>
<items>
<item>file1.dmp</item>
<item>file2.dmp</item>
</items>
<pluginExecutors>
<pluginExecutor>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.6.0</version>
<executions>
<execution>
<id>exec-one</id>
<phase>package</phase>
<goals>
<goal>exec</goal>
</goals>
</execution>
</executions>
<configuration>
<executable>imp.exe</executable>
<commandlineArgs>${jdbc.user}/${jdbc.password}#${jdbc.db.name} FILE=${project.basedir}/export/target/database/#item# FULL=Y GRANTS=N INDEXES=N CONSTRAINTS=N IGNORE=Y</commandlineArgs>
</configuration>
</plugin>
</pluginExecutor>
</pluginExecutors>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
The error message I receive is
[ERROR] Failed to execute goal com.soebes.maven.plugins:iterator-maven-plugin:0.5.1:iterator (import-file) on project test-import: Unable to parse > configuration of mojo com.soebes.maven.plugins:iterator-maven-plugin:0.5.1:iterator for parameter executable: Cannot find 'executable' in class > java.lang.Object -> [Help 1]
[ERROR]
I've looked at the optional parameters for both the iterator plugin and the exec plugin to see if there is something I can add which would allow the exec plugin to work but nothing seems related to a java error.
Has anyone run into this error before?