I use plain TeX. If, with XeTeX 0.4 I typeset a simple document using CM fonts all is well. With version .5 I get an error message: *** font cmr10 (CMR10: file 'cmr10') not found ) ...and I get a blank pdf. However, if I use, say, Optima Bold (\font\test=\"Optima Bold at 20pt \test) all is well. All I did was to update to version .5. Any suggestions?