Getting the fullname value of active presentation

FullName = Globals.ThisAddIn.Application.ActivePresentation.FullName;

Hi

I have created a powerpoint addin and there i have a ribbon with a button in it.When i click on the button is should get a fullname of the active presentation and the code that i use is as below.But it throws the following error

"The message filter indicated that the application is busy. (Exception from HRESULT: 0x8001010A (RPC_E_SERVERCALL_RETRYLATER))"

Can some one help on this?