I'm going to reply to myself here. Just found the example bib file in the
wiki and copied (replaced) my bib file with it.
Good news: Entrys show up.
Bad news: The first two entries are missing.

Since I only tried example files with two entries max, that changes the
issue description from "not shoing up" to "the first two are omitted. See
attached output pdf. (nothing changed in source except bib file content)

> -----Ursprüngliche Nachricht-----
> Von: ntg-context-bounces@ntg.nl [mailto:ntg-context-bounces@ntg.nl] Im
> Auftrag von Christian
> Gesendet: Mittwoch, 6. Juli 2011 17:08
> An: mailing list for ConTeXt users
> Betreff: [NTG-context] Bibliography entries not showing up
> 
> Dear list,
> 
> I would like to use ConTeXt (MKIV) for typesetting my thesis. So I tried a
lot
> of the features and I'm really impressed by the flexibility and so far
more
> than satisfied with the results. Now I obviously need a bibliography and
tried
> to get it working today. But whatever I tried, I can't seem to get the
entries
> to show up in the pdf.
> 
> Setup:
> Win 7 32bit
> LuaTeX, Version beta-0.60.2-2010100221 (MiKTeX 2.9) (rev 3736) ConTeXt
> ver: 2010.05.24 13:05 MKIV
> 
> Main file (example.mkiv):
> \setupbibtex[database=example]
> \setuppublications[alternative=apa]
> \starttext
> Test
> \completepublications[criterium=all]
> \stoptext
> 
> 
> Bib file (borrowed from another recent topic - hope you don't mind,
> example.bib) :
> @BOOK{daunerliebkonzenschmidt,
> author = {Peter Schlechtriem and Horst Konzen}, }
> 
> @BOOK{schlechtriemschmidtkessel,
> author = {Peter Schlechtriem and Horst Konzen and Karsten Schmidt}, }
> 
> Generated bbl file (example.bbl):
> \setuppublicationlist[samplesize={SKS},totalnumber=2]
> 
> \startpublication[k=daunerliebkonzenschmidt,t=book,
> a={{Schlechtriem},{Konzen}},y=,
> n=1,s=SK]
> \author[]{Peter}[P.]{}{Schlechtriem}
> \author[]{Horst}[H.]{}{Konzen}
> \stoppublication
> 
> \startpublication[k=schlechtriemschmidtkessel,t=book,
> a={{Schlechtriem},{}},y=,
> n=2,s=SKS]
> \author[]{Peter}[P.]{}{Schlechtriem}
> \author[]{Horst}[H.]{}{Konzen}
> \author[]{Karsten}[K.]{}{Schmidt}
> \stoppublication
> 
> Output and log file attached.
> What's wrong here?
> 
> Also, if anybody thinks mkiv is not ready for productive work, please
scream
> and stop me. But as far as I've heard it has been used to typeset books
and
> theses already, so... yeah.