The actual problem is :I had downloaded a ppc executable(I forgot the exact version,maybe 99.0?) but didn't run.About makeobj:it was included in the package apt-get provided me with,and it ran.
PS:I am reffering to the "what you need to play simutrans" article in the german wiki (probably this is also in the english wiki?).
PPS:Yes,I am using Debian now,not MacOSX.For now I don't have any problems except the map generation takes too long(900Mhz CPU,160MB RAM,512 MB swap).
PPPS:I am not sure which proccesor the mac of my mother has(pentium or ppc?),but,it lies in Bulgaria,too far away from Thailand,and,additionally,I dont know how to make a virtual pc.