Welcome to the busted netflix channel on Roku.
The good news is that it only happens to some people.
The bad news is it's happening to you - and me.
Don't worry though. It's being 'investigated' (for about a year now), so a fix is just around the corner.
The Netflix channel on Roku is NOT causing this. The same issue appears on their web site.
It looks like there are two possibilities.
1: There is a glitch of some kind at Netflix that is preventing eps 1-7 from showing. (Not likely)
2: Netflix no longer has the rights to the first seven seasons. (Probably)
There is no way Roku's Netflix channel is causing this problem and it is foolish to think so.
Netflix on Roku has some problems from time to time but this is not one of them.