Your definition of lambda.2 in Prime has the wrong units!
It should be milliohm/meter but you defined it as millimeter * ohm / meter
miiliohm is not predefined in Prime. So you may write 10^-3 ohm.
If you need it more often in your sheet, it may be a good idea to add the definition of that unit by typing

You can hide that definition at the top of the sheet either to the right of the first page margin or in a collapsed region.
For consistency the left hand side of the definition should be labelled as "unit" (so its typeface is turned bold blue).
You get the Omega (looks better than writing "ohm") by typing a capital W and immediately follow it by pressing Ctrl-G (for "Greek").
For future questions please always attach your worksheet as well and as you are using Prime its necessary to state which version you are using.