Taylor Expansion not working

[wneff]

Hello,
I have been a long time user of the 48SX and GX and just got a 50g to replace the SX.

So....and now I want to do a taylor expansion of sqrt(0.2*x+1)
So...first when i assemble the root is asks me to turn on approx mode - OK
I put on the stack
> sqrt(etc)
>'X'
>5

and i get the message: "Approx mode off"
...OK...
Next it s pop-up: "TAYLR error: Mode switch not allowed here "

hmmmmm.....works on the SX. Can someone give me a hint how to do that?

Wolfram