Stack file is invalid: component 'ST-A/PI' During sp update with SUM

Dear Experts,

            I am upgrading solution manager 7.1 to SP08 using SUM.I am facing following  error during .

Severe error(s) occured in phase PREP_EXTENSION/EHP_INCLUSION!

Last error code set: Stack file is invalid: component 'ST-A/PI' (stack release 01P_700 &lt; source release 01Q_700)<br/> <br/> If you put new packages in the download directory, use option 'init' to upload them

Please do needful.

Regards,

Snehal Patel