Sametime server installations fail on Domino 64 bit versions with "IBM Lotus Sametime xxx, NNNN requires Domino to be installed before Sametime can be installed, but no Domino installation was detected. Install Domino and then install IBM Lotus Sametime xxx, NNNN.
Where xxx represents your Sametime version being installed and NNNN represents the type of installation such as Lotus Sametime 8.0.2, Instant Messaging Limited Use.
Unable to install Sametime
Resolving the problem
Windows and UNIX 64 Bit versions of Domino are not currently supported at this time All present releases of Sametime up to 8.0x are based on 32bit. and are incompatible with the 64 bit version of the Domino server.
Title: FAQ: Support for IBM Lotus Domino (versions prior to Domino 8.0.1) on 64-bit Operating Systems
Doc #: 1233872
Additional information is provided in technote
Title: FAQ: 64-bit version of Domino
Doc #: 1296452