is some one can tell me why is this error?
and how solve it  without turn off pc?
thans

Is that inside Mach?

When does it show up?

What motion controller are you using?

pokeys
when run mach

As administrator, run:

netstat -a -b -n

That will tell you which program has port 50003 open.  Then you can kill the offending program in the task manager and re-start Mach. 

Some programs use random ports when they startup and that will then cause a port conflict if they start up on a port that Mach uses.  The chances are that when restarting the PC, that program (whatever it may be) will not again use the same port range.

The real fix is to remove other programs that are not needed for a machine controller. 

However, If you have to have a program that uses these port ranges, you can change the starting port that Mach uses by adding

BaseIpcPort=<some other starting port number>

to the Preferences section of the Machine.ini file in the profile's directory. 

e.g.

[Preferences]
BaseIpcPort=45000

Steve