SAP Business Objects Client 4.2 SP5 Upgrade to SP6

Hello, there,
we have a problem installing the SP6 upgrade on a Windows 7 client. SAP Business Objects 4.2 with the SP5 kontte can be installed without problems. When we start the setup routine for SP6 we get a termination message a short time later. However, the log only states that copying from the unpacked source to the target directory is not successful. All rights are granted and UAC is disabled. The installation is done as administrator. My question someone knows this error and can help us.