Spectre 16775 Warning

Hi,

While running reliability analysis for UMC90nm i am getting the following warning message. 

Warning SPECTRE 16775: Cannot run the aged model because one or more 'gradual_aging_alter' statements have been specified in the reliability block but the aged devices are either not specified or the age values of the all devices are less than the minage value.......

Please help to sort out this issue

thanks,

Deepa Mohan