Unable to connect to Analysis Services

If you are running multiple instances of Analysis Services on your machine (I am running MSSQLSERVER2008 - which is default instance - and MSSQLSERVER2008R2), you may get the following error when connecting to the non-default instance (via SQL Management Studio - NOTE: connect with MACHINENAME\INSTANCENAME):

No connection could be made because the target machine actively refused it 127.0.0.1:2382 (System)

I solved the problem by running the SQL Server Browser as LOCAL SYSTEM instead of NETWORK SERVICE. Open 'SQL Server Configuration Manager' -> Right click 'SQL Server Browser' and open the properties -> Chose 'Local System' as Built-In account in the 'Log on as' tab