During our development we found out that

During our development we found out that if the mdx cube script definies named sets that are very performance intensive to generate - this will considerably slow down the loading of the cube in Excel 2007. we also a few times received the error message: Excel was unable to get necessary information about this cube. The cube might have been reorganized or changed on the server. Contact the OLAP cube administrator and, if necessary, set up a new data source to connect to the cube but after removing the named sets from the mdx cube script we were able to open the cube in Excel 2007