SAP NetWeaver Trial 7.03 64bit: sapinst Phase 15 Import ABAP fails with SAPSYSTEMNAME

When installing SAP NetWeaver Trial 7.03 to Windows 7 Prof the execution phase 15 (Import ABAP) fails with these messages

################################################

Abort execution because of

controller.userDecideToStop

##############################################

INFO       2014-07-03 16:32:03.38 [synxcpath.cpp:814]

           CSyPath::createFile() lib=syslib module=syslib

Creating file C:\Program Files\sapinst_instdir\.lastInstallationLocation.

CGuiProxy::receive(): connection on socket 580 closed by peer

=>sapparam(1c): No Profile used.

=>sapparam: SAPSYSTEMNAME neither in Profile nor in Commandline

Exit status of child: 2

I found several discussions ont SAPSYSTEMNAME, but unfortunately I have not been able to learn how to overcome this problem.

Thanks for any help!