I forgot to mention, I compiled and ran the program on Irix 6.5.5 with SGI CC 7.3 and that ominous patch removed both in debug and optimized version. -- Nils H. Busch Max-Planck-Institute of Cognitive Neuroscience phone: ++49 (341) 9940-335 fax: ++49 (341) 9940-204 e-mail: nilsb at cns.mpg.de