Getting Error when retrieving an xlsx file from sharepoint using SPFile.openbinary();

I am using the below code to retrieve the files from sharepoint to byte[].

SPFile file = currentWeb.GetFile(item);

byte[] dat开发者_StackOverflowa = (byte[])file.OpenBinary();

I am getting the below exception, when i am retrieving xlsx files from sharepoint:

Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack

Can any one have an idea about it.........?