Since a while I obtain an error message trying to compile gretl-ref.pdf. The concrete error message is: -------------------- ! Text line contains an invalid character. l.86 ^^@ ^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^... ? ! Emergency stop. l.86 ^^@ ^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^... ! ==> Fatal error occurred, no output PDF file produced! Transcript written on gretl-ref.log. make[2]: *** [gretl-ref.pdf] Fehler 1 make[2]: *** Warte auf noch nicht beendete Prozesse... ! Text line contains an invalid character. l.86 ^^@^^@ ^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^@^^... ----------------------- I also attached the "gretl-ref.log" file for more information. Artur