Q: I'm using SAP which uses Kerberos version 5. Can that be causing me problems with Kerberos version 4?
Not if you have the most recent versions of Kerberos for your platform.
In the most recent versions of Kerberos for both Macintosh and Windows, versions 4 and 5 are joined. They use the same ticket cache and are the same application.
If you are not using the latest version of Kerberos for your platform, you should upgrade now. Go to Security Software.