1)  It's unfortunate that you are having problems, my runtime libraries seem (knock on wood) to be running fine right now--I've loaded up new stuff and old stuff--Generation 1 Daz figures and other Poser stuff.  M4 and M2--no problems here.  It could have something to do with location of the runtime, or changes that have been made to it.  I placed my Poser Runtime library in My Documents folder on Vista.  I let Poser 8 install the new runtime into it's default new location.  I used the add runtime library button to add my libraries to the libraries pallate.  Perhaps making other choices mucks things up.

2)  Every time I buy I new program, it seems there are major bugs.  When I try to movie a light, for instance, with the tranlate too it goes spinning off into space somewhere--but using the parameter dials works fine.

3)  I've had major probems with the Poser 4 render engine creating weird artifacts on my pictures in Poser 7.  I'm not sorry to see it go personally, you can scale down your render quality for quick and dirty test renders.

4)  Almost no one is including a printed manual anymore and if they are available you usually have to pay extra for them.  Not even Adobe Photoshop comes with one since CS3; you'd think that high end software costing many hundreds of dollars would.  For the most part I've found that included manuals for programs are inadequate, I've always purchased 3rd party books to fill the gaps and that works well for me.  You might want to try Poser 8 Revealed or Practical Poser 8--I think that Practical Poser 8 would probably be the best choice for someone with Poser experience--my past edition of the Poser Revealed was extremely basic.

I remember Poser 5 was so bug ridden for the first 2 years it was out I could not use it, so I was using Poser 4 Pro Pack for a while.  By the time they got Poser 5 right, Poser 6 was released.  I don't think we'll  have to wait that long in this case--Curious Labs was very slow to release patches.