Application gets hanged with multiple instances of a thread in VB.NET 2005

<p>Hello.</p><p>We are developing an application which requires multi-threading. The thread has to run as long as the application is running. The application runs properly as long as there is only one instance of the thread. In case we start 2 instances of the same thread the application gets hanged after 15-20 minutes. We have used SyncLock for shared resources and&nbsp;delegates for updating GUI from thread. Still the application gets hanged.</p><p>Sometimes we get the following exceptions:</p><p>1) An unhandled exception of type 'System.ExecutionEngineException' occurred in mscorlib.dll</p><p>2) .NET Runtime version 2.0.50727.3643 - Fatal Execution Engine Error (7A0BCA72) (80131506). ==&gt; This gets recorded in the "My Computer-Manage-Event Viewer-Application"</p><p>Sometimes the "Memory Usage" seen in the Task Manager goes on increasing for our application.</p><p>Please guide us to solve the issue ASAP.</p><p>Thanks in advance.</p>