COM Errors on page

Question

User-577991800 posted

using ASP.NET 4.0

there is a COM Dll I am using on a page. I have deployed this on test servers (the website) and also on my local dev environment with NO problems at all.

 

However on the live site after deploying (and registering the COM Dll), I always get this error and no idea where to go:

 

Unable to cast COM object of type 'OnlineUtils.clsMainClass' to interface type 'OnlineUtils._clsMain'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{B0B5FC90-90A9-4DD9-A4C6-D779C905B322}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).
   at System.StubHelpers.StubHelpers.GetCOMIPFromRCW(Object objSrc, IntPtr pCPCMD, Boolean& pfNeedsRelease)
   at OnlineUtils.clsMainClass.GetCertFileList(Object& sPath)
   at OnlineWebsite.Report.CalDisplay.DoDisplayCertAndData() in C:\Users\Tech\Documents\Visual Studio 2010\Projects\OnlineWebsite\Report\CalDisplay.aspx.cs:line 369
   at OnlineWebsite.Report.CalDisplay.DoPreparePage() in C:\Users\Tech\Documents\Visual Studio 2010\Projects\OnlineWebsite\Report\CalDisplay.aspx.cs:line 79
   at OnlineWebsite.Report.CalDisplay.Page_Load(Object sender, EventArgs e) in C:\Users\Tech\Documents\Visual Studio 2010\Projects\OnlineWebsite\Report\CalDisplay.aspx.cs:line 48
   at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e)
   at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e)
   at System.Web.UI.Control.OnLoad(EventArgs e)
   at System.Web.UI.Control.LoadRecursive()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

 
 
Request information:
    Request URL: http://www.xyz.co.uk/TheSite/Report/CalDisplay.aspx?cn=090010OTBOTest
    Request path: /TheSite/Report/CalDisplay.aspx
    User host address: xx.xx.xx.xx
    User: username
    Is authenticated: True
    Authentication Type: Forms
    Thread account name: NT AUTHORITY\NETWORK SERVICE
 
Thread information:
    Thread ID: 9
    Thread account name: NT AUTHORITY\NETWORK SERVICE
    Is impersonating: True
    Stack trace:    at System.Web.UI.Page.HandleError(Exception e)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest()
   at System.Web.Util.AspCompatApplicationStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

 

 

The difference is that The live server is using IIS 7.0 WS2008 and my test server and dev env is WS2008R2 and IIS 7.5

 

any ideas where I am going wrong?
 

Answer 1

User-166373564 posted

Hi ahmedilyas

Unable to cast COM object of type 'OnlineUtils.clsMainClass' to interface type 'OnlineUtils._clsMain'. .....

From the error message above, there is something wrong during your COM Dll register, and you need register your COM Dll again,

Regards

Answer 2

User-577991800 posted

Tried that too and no go.

The problem was that there was a duplicate (an older version) located in a different directory which I had no idea about.

I unregistered and deleted that DLL then re-registered the new DLL and all worked fine.