POA-93811 Subscription migration fails via Migration Manager if HCL Transfer file more than 8GB.
Hotfix can be downloaded here.
Use pa_updates_installer (http:/kb.odin.com/111323) to install this hotfix. Also this hotfix will be installed automatically during upgrade to OA 5.5.9 via pa_updates_installer. To install hotfix manually obtain its distributive from the link above and follow instructions found in file UPDATE.txt of distributive.