Hi vectordez.

It appears that you may have a corrupted file or files.

Please uninstall Export Content from the Mambo Site and check that all files have been removed from:
/administrator/components/com_export_content/
And
/components/com_export_content/

Then re-install Export Content version 1.0.0 on the Mambo site.

Then on the Joomla 1.0+ destination site do the same thing then re-install Export Content version 1.7.0

Another thing to check after everything has been re-installed is make sure:
/administrator/components/com_export_content/new_version
/administrator/components/com_export_content/img
/administrator/components/com_export_content/zip
Permissions are set to 777.

Please post back and let me know how you get on.