Following an earlier suggestion to get more help: I am trying to install VMware 4.5.2-8848 on 64 bit system, new installation of 9.2, online updated to 2.6.8-24.5 default kernel. Build seems to proceed fine, but configuration fails while building vmmon.o module, at second step, quoting a reply I have from an earlier plea for assistance: "Your error happens in the piece of code starting #ifdef MODULE_X86_64 in hostif.c" and this does seem to be the case, as error messages start here, and failure occurs quickly. Are there some steps to use vmware workstation on a 64 bit system that are different from the 32 bit, other than waiting for vmware to write the modules and post them? Thanks for any other assistance. Richard PS: Thanks to Kastus, Bruce, and Luis-Miguel for getting me this far.