There may indeed be a problem with the rpm.
Look at the directory it seems that the sizes are quite different !
lesstif-0.90.0-1.src.rpm 3870 Kb Sun Apr
16 21:55:00 2000
lesstif-0.91.0-1.src.rpm 3267 Kb Tue May
16 21:59:00 2000
When I downloaded it and tried :
$ rpm -vv -qilp lesstif-0.91.0-1.src.rpm
D: New Header signature
D: Signature size: 68
D: Signature pad : 4
D: sigsize : 72
D: Header + Archive: 3345710
D: expected size : 3475502
query of lesstif-0.91.0-1.src.rpm
failed
Try taking the tar.gz file for the moment, until a new rpm is built.
CP