what is < error using ==> open at 158 > in matlab simlink window ?

i got problem at opening a file .slx in R2009a, how it can be eleminate this error 158

[Jan]

All we know is the line in which open fails, but no further details. It is impossible to suggest a way to fix the problem without any further knowledge. So please edit the question and explain much more details: Which Matlab version has been used to create the file? Did the file work successfully before? Copy the complete error message.