Thanks to Tom and Adriaan, my compiler in in order on Mac OSX (but before trying to load the Developper Tools CD from USA1 and not from Europa, I was desesperate). Yet, other problems are coming... 1) PATH problems 1a) I'm unable to execute the a.out (nor the hello if using -o) directly but must use the stupid ./a.out (or ./hello). Even if I redefine the variable PATH in ~/.tcshrc (adding to it the current directory .). Where lies the file who defines PATH ? 1b) I construct some modules for toolboxes (like timer.p) or for abstract types (like lists.p) and I would like to put them in a genuine directory such that the compiler could find them from any other directory : how do it ? 2) export problem If I construct a module to implement an abstract type such that rational numbers, how export operators ? Writing : export rationals = (rational, +, -, *, /) ; give me a parse error before '+' (trying to enclose + between ' ' or " " is useless) Thanks in advance, Dominique