This is due a "bug" in in LyX. The workaround is at this thread: http://www.mail-archive.com/lyx-users@lists.lyx.org/msg86089.html
I don't know what causes this and why changing this configuration solves the problem, but I am forwarding this again to devel list. --- Diego Queiroz 2011/4/13 Richard Heck <rgh...@comcast.net> > On 04/13/2011 05:03 AM, Ville Iiskola wrote: > > Hi > > I tried to convert my Lyx- file into PDF-form but the adobe reader just > opened but the file did not open.. > What could be the problem? > > > This probably means there was an error and the file was not produced. I > guess the next question is: What was the error? > > Richard > >