If two or more STRATA variables with associated labels are specified in PROC LIFETEST and a survival plot is generated with ODS Graphics enabled, SAS might freeze or issue one or more of the following errors:
A survival plot is generated by default when ODS Graphics is on, or it can be specified with the PLOTS=SURVIVAL option in the PROC LIFETEST statement.
To circumvent the problem, specify the NOLABEL option in the STRATA statement or suppress the survival plot. To suppress the plot, you can specify the PROC LIFETEST option PLOTS=NONE or use PLOTS(ONLY)= to generate other plot types.