squid830: Have you done any more on Dr. Glar's Parcel? Or Source? Where are you up to on those quests?
Sorry if I'm not more helpful, I haven't played this in ages. I do recall having to do a task that was only tangentially related to this quest (ie not directly one of the quest tasks) before Riebel would speak to me.
There might be something you need to do in the dream world to advance? What point are you at in that quest? From memory, there's a reasonable amount of stuff you can do on your first visit, which involves solving the quests for the three shadow characters in there - or have you already done that bit?
I vaguely recall that Thyper doesn't actually "show up" until after you talk to Riebel about it (which you obviously cannot do right now).
It's definitely a shame about this game - the atmosphere is top notch, the graphics are quite nice, the overall plot is interesting (if bizarre). Unfortunately it's still a buggy mess, and they haven't even fixed really simple things like Thyper's health bar showing up when he's a companion, and for reasons unknown the camera is unable to be tilted in the vertical direction (despite the fact that I'm pretty sure the "lack of textures" in those directions isn't an issue - it wouldn't bother me if there weren't many locations where there are literally things above and/or below you to look at! Hell there's even one part where the conversation is really awkward because the dude you're talking to is on a higher level than you, and you can't actually look at him!).
Say10: This is the problem. The quest with parcel is indicating I should follow the Riebel's assignment...
OK so you've obviously progressed that one as far as you can for now...
What about source?
TBH I'm kind of clutching at straws here, since it's been a while since I played this. I know I never had this problem, but I've also seen almost the exact same issue crop up for other users in the version I played then (1.5). Given how many bugs there are in this game, it wouldn't surprise me if this is yet another one - but at the same time, if there are other main quests to do, it might be worth going on with them to see if it changes anything...
Although quests aren't clearly marked as main quests or side quests, the ones in your list that I'm pretty sure are "main quests" would be: "What is the price of freedom", "Dr Glars parcel", "Source", "Prison Inside". and "Bane of Mills". You seem to be blocked on all except possibly "source" - if you're blocked on that too, then I'd say you've almost certainly hit yet another bug.
Have you contacted the devs? Maybe they can at least definitively tell you whether it's a bug or not, or possibly provide a workaround or save fix?
Other than that, I have no idea. This bug has been intermittently around since before 1.5 apparently, but it was pretty rare so I don't think anyone actually knows if it's even an actual bug, let alone what causes it...