You stated that "It single-handedly rendered any song with EWQL plug ins unable to be opened"
What safe will allow you to do is to open the project but selectively bypass the EWQL plugins in the process, which may allow you to al least open the project(s). (albiet without the EWQL plug ins loaded)
To roll back to the previous version of Platinum, you open up the Cakewalk Command Centre, Right click "Platinum" and select "Rollback" and then select the version that you wish to roll back to.