1) Have you installed Csound5?

  2) Are you environment variables set up correctly?

     A good way to check is to open up a DOS prompt.  cd to some directory other
     than the Csound5 bin directory.  Run the command "csound".  If that fails,
     then your environment variables need to be set properly.

     Right-click on "My Computer", select "Properties".  Switch to "Advanced" tab.
     Click "Environment Variables" button.  Look for "PATH" and check to see if
     your Csound5 bin directory has been appended to it.  Look for "OPCODEDIR" or
     "OPCODEDIR64", depending on which version of Csound5 you installed.  If they
     are not present, then add them.

     When modifying the "PATH" environment variable, it's a good idea to modify
     the user variable rather than the system variable.  

  3) If you installed the 32bit version of csound~, then you must have 32bit Csound5 installed
     in order for csound~ to run.  The same goes for 64bit csound~ and 64bit Csound5.  
  
     Consult the installation instructions for tips on which Csound5 installers to use.

  csound~ cannot run Csound4.  Max is loading Matt Ingalls' csound~ rather than
  my csound~.mxo.  To fix this problem, remove Matt Ingalls' csound~ object from
  the externals directory.  If it's not there, then it is somewhere else within Max's search path.

  Search all directories within Max's search path (including ones that you have added
  via the Options->File Preferences... menu item).  Remove any files named "csound~".

  1) If you're using an absolute pathname in the "csound" message, then you have 
     made a mistake.  Correct the pathname.

  2) If you're using relative pathnames in the "csound" message, and the relative
     pathname is correct, then the directory that contains your patch is within
     Max's search path.  
    
     Move the directory containing your patch to another location outside Max's
     search path, or use absolute pathnames in your "csound" message.

  This problem is usually caused by dll files not being found.

  1) Make sure the version of csound~ you are using is compatible with the version of
     Csound5 that is installed.  See the installation instructions for details.

  2) Navigate to your Csound\bin\ directory and look for csound32.dll.5.1 or
     csound64.dll.5.1.  If you're using 32bit csound~, then csound32.dll.5.1
     should be there.  If you're using 64bit csound~, then csound64.dll.5.1
     should be there.