DDE Server Window:AcroRd.exe - Application Error

Hi running Windows 8.1 and problem only occurred recently. When opening a PDF in Acrobat Reader DC get the following error message:

The instruction at 0x5975525c referenced memory at 0x00000000. The memory could not be read. Click on OK to terminate the program.

Thus whilst the PDF is opened the above error message prevents the document from being read. I have tried repairing ADOBE reader and uninstalling and reinstalling but the same error persists.

Any ideas gratefully received

Thanks

Rob