It's not possible to import Pega7UpgradeAccelerator.jar (see https://pdn.pega.com/exchange/components/pega-7-upgrade-accelerator-pack) because of the error: Pega7UpgradeAccelerator.jar is an empty PegaRULES archive, and therefore there is nothing to display or import. Exception: Failed to create archive for: Pega7UpgradeAccelerator.jar (PRRuntimeException)
Please let us know how should be possible to install such assessment tool in Pega 6.1 SP2 environment (there is no Import Wizard in this Pega version, which seems to only be available after Pega 6.2).
It is not possible to run the accelerator pack against 61sp2. This is only designed to be imported on a 7x env. There are other pre assessment tools you can install on 61sp2 available at https://community.pega.com/start-upgrade