Hi Taco, hi Hans, hi everyone, With LuaTeX 0.25.4 from the TeX Live distribution, I get a strange behaviour when, in a texlua script, I call another texlua script which in turn calls a program, depending on the sequence os.spawn and/or os.execute I use. Example, assuming acrord32 is in the PATH and presentation.pdf exists: % wrapper.tlu kpse.set_program_name("texlua") os.spawn('texlua d:/mpg/program.tlu') -- or... -- os.execute('texlua d:/mpg/program.tlu) % program.tlu os.execute ('acrord32 "d:\\mpg\\presentation.pdf"') -- or... -- os.spawn ('acrord32 "d:\\mpg\\presentation.pdf"') Now if I run 'texlua wrapper.tlu' from a command line, when Adobe Reader 9 starts, it immediatly crashes showing an error box "internal error". The problem disappears under one of the following conditions: 1. Change os.spawn to os.execute in wrapper.tlu and/or os.execute to os.spawn in program.tlu. 2. Do the same on linux (with trivial path adaptations). 3. Use something else than Adobe Reader (or Adobe Acrobat) 8 or 9. 4. Comment the call to kpse.set_program_name(). I tend to believe that 3 and 4 a rather anecdotic, and though in theory the problem could come from kpse or AR, it may actually be more related to os.spawn. A quick look at loslibext.c let me think that os.spawn is indeed rather tricky on windows (and at least more than on *nix). So, what do you think? Is it a bug or I am doing something wrong? Thanks, Manuel.