The problem you describe is that your R: drive isn't available to the Worker at execution time. The other errors are just script errors derived from fact that the After Effects Job Type execution module lives in c:\program files\pfx\jobtypes\aftereffects.
I recommend you launch the Configuration GUI on your submit host, and use Windows Drive Map to configure a drive map for R:. Input the appropriate credentials (you can use DOMAIN\USER format in the user area, and when you submit the job, the necessary information for giving the Worker access to map the share should be sent along with the job.
