ipcBeginProcess not stable on batch mode

Hi, Initially, I use ipcBeginProcess to run the command shown in the bottom using batch mode like the following

icms -nocdsinit -nograph -noblink < /home/irdc/users/wtjong/projects/MSD/shawn/fxdac260/ftc_porting.il

But it doesn't work most of time and the same thing happens using the GUI mode via CIW. Therefore, I remember that from some post, if I don't talk to the process, then just use csh, system, etc. So, I do that and it works perfectly as I expect. But I don't understand why and it is very difficult to trace down the problem because ipcReadProcess(cid) shows nothing at all. Anyone knows how to trace down this problem or any clue to do so? I don't know if I have luck next time if I need to use ipcBeginProcess. Thanks.

 sprintf(info_str "/home/irdc/users/wtjong/work/designkit/optimization/utility/msd2.new/libChar/post_sim_find %s" fc)

 printf("%s\n" info_str)

 ;cid = ipcBeginProcess(info_str);

 ;ipcWaitForProcess(cid)

 system(info_str)

 Best Regards, Wells Jong