You can only have one -command attribute per Button widget. You might try:

-command => sub {$e1->delete(0,'end');
                 $e2->delete(0,'end');
                 ...
                 $e5->delete(0,'end');
                }
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Or better yet, instead of sub, use a reference to an actual subroutine so your button declaration isn't so messy and that way you can call the resulting sub from other places in the script if needed.