Thanks Jack for your comments. I guess some clarification is needed. The PayPal App I downloaded was 5.010, but when I installed it, I recall that it installed some updates. I see now that I have version 5.018. I assume that is the current version. As for the emails, you are right that PayPal does not send out its emails, but they are available in the sandbox. I am concerned about the confirmation sent by osC and some custom emails I have created. I use the Send Mail Server Tool which is a handy little tool which gets around having to configure an email server in PHP. It captures the messages that osC attempts to mail and stores theme in a directory on my server. Those emails are not forthcoming, and they are the ones I am concerned about.
Any information you, or anyone else, might have about the program flow in processing checkout would be appreciated.