I had already tried the instructions suggested in sticky post: http://www.tecplottalk.com/viewtopic.php?t=61
but I already had those rpms, so that wasn't the problem.
Further investigation still suggests that it might be a glibc version problem - I can do the usual trick of putting in a symlink from libm.so.5 to the current libm version, but this merely throws another error. The Fedora Core 6 (for x 86) version of glibc is glibc-2.5-10.fc6. Can anyone confirm that it is a glibc problem and not something else?
I haven't followed the evolution of the tecplot product line since I bought tecplot v10 - I guess I was hoping that there might be a tecplot 10.x build tthat would work with this glibc version. It's good to know that Tecplot360 is OK with FC6, but that doesn't help me right now.
The alternative is to try to find a way of having older glibc versions available for tecplot, but it's easy to damage one's Linux install if this goes wrong (as I've discovered). Advice here would be appreciated too.