Synchronous vs Asynchronous dispatch calls

Hi, all.
In my project I'm using MSComm RS232 control to communicate with device. There is an event handler in application. This application is a server for clients, that are implemented as ActiveX controls. When data arives from COM port, the MSComm fires an event. In my event handler I want to notify clients that data is ready, but I've got a problem of calling their dispatch functions from within a handler. Something like "An outgoing call cannot be made due to the synchronous incoming call". Have you ever had that problem? I'd be so happy to find a solution. Could you help?