BPC 10 NW Error launching excel from BPF activity in web client

Hi,

App Server version : BPC 10 NW SP 09

Client version :  EPM 10 SP 13 patch 5 .Net4 client for big volume.

We have one user that is getting the following error when launching a excel input schedule from a activity in a BPF in the web client.

Error Launching office client : Interface not registered ( Exception from HSRESULT:0x80040155)

Users machine : Windows 7 64 bit , Excel Offce 2010 32 bit , Internet explorer 9 32 bit , EPM Add-in 10 SP 13 patch 5 .Net 4 big vol.

Any ideas why the user receives this error message.

Thanks

Gavin