Dryer Questions.

[BackPackHunter]

I'm doing some renos , and the washer & dryer need to be moved to keep the boss happy, and I ran into a little problem. Figure I'd ask the mines of AO

On the power cord it there's a sticker saying Do Not use an extension cord
Problem is the plug wire might be 40 inches long.
Why can't I use an extension cord?
I really don't want to get a new wire , open the wall move insolation and drill the studs, wire it , then get someone to tie it into the panel then close the wall,

This is turning into a big can of worms to move the dryer 6 feet

Thanks