thanks I'l try and sorry about posting the hole error

in powder.c I have:
if(*x <= 0 || *x >= XRES-1 || *y <= 0 || *y >= YRES-1)
in powder.h I have:
{"", PIXPACK(0x000000), 0.0f, 0.00f * CFDS, 1.00f, 0.00f, 0.0f, 0.0f, 0.00f, 0.000f * CFDS, 0, 0, 0, 0, 1, 1, 100, SC_SPECIAL, R_TEMP+0.0f +273.15f, 251, "Erases particles.", 0, NULL},

And now the error has changed to:
1>------ Build started: Project: PowderToy, Configuration: Release Win32 ------
1> air.c
1>src\air.c(2): fatal error C1083: Cannot open include file: 'air.h': No such file or directory
1> graphics.c
1>src\graphics.c(2): fatal error C1083: Cannot open include file: 'SDL/SDL.h': No such file or directory
1> http.c
1>src\http.c(45): fatal error C1083: Cannot open include file: 'defines.h': No such file or directory
1> interface.c
1>src\interface.c(7): fatal error C1083: Cannot open include file: 'bzlib.h': No such file or directory
1> md5.c
1>src\md5.c(3): fatal error C1083: Cannot open include file: 'md5.h': No such file or directory
1> misc.c
1>src\misc.c(4): fatal error C1083: Cannot open include file: 'misc.h': No such file or directory
1> powder.c
1>src\powder.c(3): fatal error C1083: Cannot open include file: 'defines.h': No such file or directory
1> update.c
1>src\update.c(40): fatal error C1083: Cannot open include file: 'update.h': No such file or directory
1> Generating Code...
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========