SystemModeler 4.0.0 and Mathematica ProductTrial 10.0.1.0 on Mac OS X 10.9.4
What version of SystemModeler and Mathematica are you using? There was a problem with SystemModeler 3.0.0 and Mathematica trial.
I did clear the kernel, and reconfigure the connection between SystemModeler and Mathematica - the configuration apparently went fine. However, I experienced the same problem again. Is it because I am currently using the product trial of Mathematica? Or is there some other problem?
Try removing the contents in this file (after backing up a copy of the file):
FileNameJoin[{$UserBaseDirectory, "Kernel", "init.m"}]
Then reconfigure the WSMLink through SystemModeler -> Options -> Mathematica -> Configure SystemModeler Link
