Content object export is a time consuming task which often exceeds the default configured request timeout, http://google.com/search?q=http+request+timeout
I would recommend turning to the eZ Publish command line tools instead which are not affected by http request timeout dependencies.
You can review, ezpm.php, http://pubsvn.ez.no/nextgen/trunk/ezpm.php http://ez.no/ezpublish/documentation/ez_publish_3_4/content_object_export_with_ezpm
Though I will warn you, I believe there are outstanding issues with certain uses of this component.
I might instead offer an alternative, use the csvextract extension to extract your content and use the features of 3.9 to import your csv!
* Package system:
- Command line package tool 'ezpm.php' updated:
o 'list', 'import', 'install' command have been changed to match admin
interface functionality.
o Implemented suggestion #010001: 'ezinstallscript' and 'ezextension' items are
supported by 'add' command.
o Implemented suggestion : Allow ezpm to set vendor.
(Merged from trunk (3.10.0alpha1) rev. 17983)
Based on my experience, packages between version don't work smootly. I'd suggest to copy the db and do an update by hand with the provided mysql/postgres sql files+run the php if needed.
