MS Dynamics 2011: Could not load file or assembly ‘Microsoft.Crm, Version=5.0.0.0,

we have recently set up a windows 2008 R2 Server with Exchange 2010.

Now one of our admins was advised to install MS Dynamics 2011 on that server as well.

It seemed to work as we can access the CRM stuff. But our smartphones (iphone) and our mac e mail clients cannot access https://SERVER/owa as there is happening a 500error, internal server error.

After we had a look in the event log, we found:

Event code: 3008 
Event message: A configuration error has occurred. 
Event time: 04.04.2012 09:01:27 
Event time (UTC): 04.04.2012 07:01:27 
Event ID: 9cf5f5e4b1cc4b088de4c88e9b8d369b 
Event sequence: 1 
Event occurrence: 1 
Event detail code: 0 

Application information: 
    Application domain: /LM/W3SVC/1/ROOT/EWS-7-129779964874694509 
    Trust level: Full 
    Application Virtual Path: /EWS 
    Application Path: C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\exchweb\EWS\ 
    Machine name: WIN-1VCFHUAVVGT 

Process information: 
    Process ID: 7324 
    Process name: w3wp.exe 
    Account name: NT-AUTORITÄT\SYSTEM 

Exception information: 
    Exception type: ConfigurationErrorsException 
    Exception message: Could not load file or assembly 'Microsoft.Crm, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. Das System kann die angegebene Datei nicht finden.
   at System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective)
   at System.Web.Configuration.AssemblyInfo.get_AssemblyInternal()
   at System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig)
   at System.Web.Compilation.BuildManager.CallPreStartInitMethods()
   at System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException)

Could not load file or assembly 'Microsoft.Crm, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. Das System kann die angegebene Datei nicht finden.
   at System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection)
   at System.Reflection.Assembly.Load(String assemblyString)
   at System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective)



Request information: 
    Request URL: https://192.168.0.1:443/EWS/Exchange.asmx 
    Request path: /EWS/Exchange.asmx 
    User host address: 192.168.0.3 
    User:  
    Is authenticated: False 
    Authentication Type:  
    Thread account name: NT-AUTORITÄT\SYSTEM 

Thread information: 
    Thread ID: 11 
    Thread account name: NT-AUTORITÄT\SYSTEM 
    Is impersonating: False 
    Stack trace:    at System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective)
   at System.Web.Configuration.AssemblyInfo.get_AssemblyInternal()
   at System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig)
   at System.Web.Compilation.BuildManager.CallPreStartInitMethods()
   at System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException)


Custom event details: 

I googled around and found this:

http://nishantrana.wordpress.com/2011/01/20/could-not-load-file-or-assembly-microsoft-crm-version5-0-0-0-cultureneutral-publickeytoken31bf3856ad364e35-or-one-of-its-dependencies-the-system-cannot-find-the-file-specified-or-deploying/ and I've already tried this, but it won't help.

Any ideas on that?

Thanks in advance!