[j-nsp] trying to upgrade OS on M5, getting "not compatible" error

[Mickey Everts]

I have an M5 which is running kind of an old version, JUNOS 5.6R2.4.  
When I attempt to upgrade via this command:

request system software add validate reboot 
/var/tmp/jinstall-7.6R4.3-domestic-signed.tgz

I received the following error...

WARNING: Current configuration not compatible with 
/var/tmp/jinstall-7.6R4.3-domestic-signed.tgz

For the hell of it, I tried 
instead"jinstall-6.3R3.1-domestic-signed.tgz", but received the same 
error. 


What would be the best way to proceed?  We depend on this router and 
need to keep downtime to a minimum.  The error message is not exactly 
chock full of details.  What would happen if I left off the "validate" 
part of the command?

Thanks in advance for any help on this....

Mickey