I've been streaming videos fine with JW Player and Wowza Media Server Pro (RTMP) and watching videos myself has been no problem. We just tried having everyone at the office try to watch the videos at the same time and get the "Stream Not Found" error.
We tried this after some clients reported getting the "Stream Not Found" error
It looks to me like our server is overloaded. Wowza shouldn't be restricting concurrent users since it's the Pro version (the free one only allows 10 concurrent connections) so I guess our server is overloaded (or some related hardware/network problem).
Is there documentation that outlines exactly what each error message means, particularly "Stream Not Found"?
Any other ideas?

I've been having the same issue with our clients. We use RTMP and Red5 server. About 95% of the clients can view the videos no problem, but the other 5% can't and get the error message saying "stream not found". Any suggestions as to why this may be happening? Blocked port? Over loaded servers?