The C program is closed, so i cannot even give the source of it. As for the Pascal, as i said, it's not mine, i cannot distribute the sources.
The external program is running fine, it communicates via serial port and i see the LED blinking. If the programs tops, the LED stops blinking. And it does not matter if i use CommandLine or the new methods, i've checked the parameters and all is fine...
You don't have to give the same source code, create yourself one that demonstrates the behavior, as simple as possible.
In that case, the program might really be running, but buffers its output. Again this is just a guess. One more thing, it could actually be writing to stderr instead of stdout, so you might want to add poStderrToOutPut to Options property.