PermGen space error when restarting Tomcat

I have successfully installed OpenMRS and now trying to incorporate the modules. We are implementin OpenMRS on a Windows Server but now we’re having issues with Tomcat. The following is the error we get after pasting the modules to the /modules directory and trying to restart the Tomcat: Tomcat – java.lang.OutOfMemoryError: PermGen space

Any help is appreciated! Thanks!