I am also receiving a "Class not registered.." error when I try server-side image conversion using your ServerSideImageHandler api.. This works in a local environment using the sample code you sent, however it results in this error in our production environment.
Exception: System.Exception
Message: Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
StackTrace: at FusionCharts.ServerSideHandlerBase.initializeObjects()
at FusionCharts.ServerSideHandlerBase.setParameters(String swfPath, Int32 width, Int32 height, String dataXML, String dataURL, String imageFileName)
at FusionCharts.ServerSideHandlerBase.startProcessThread(Object oSSH)
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.runTryCode(Object userData)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart(Object obj)