It's clear now where the problem is..
I thought that nasm has some code dealing with OS particularities (specifically the file operations), but the doc states that it doesn't, so when the search path (-i's argument), which includes the quotes, is appended with the file name when the include file needs to be open, the result is an invalid path.. and because the output file and input file parameters aren't touched, Windows understand them..
And this was bugging me, one quoted path worked, and the other don't..
The error from nasm is indeed "no input file specified", and all file/directory names are without spaces in them (that "c:\my project" was just an example)... the idea is that i'm calling nasm from "visual c++" which appends quotes to every path, no matter if there are spaces in file/directory names or not... the workaround is that i have to manually edit the project file to delete those quotes for the -i's argument, which is frustrating..
ehh.. i'll work a little extra to script that.. also I will try the NASMENV variable to see how it goes..
Thanks a lot Frank for your replay!
Cheers!
gpeter