Stan -

>a := OrderedCollection with: 1 with: 2.
>b := OrderedCollection with: 3 with: 4.
>a with: b collect: [:x :y | x + y]
>
>produces a walkback, because with:collect: creates a new, empty OrderedCollection
>to hold the answer, then tries to at:put: the answers there. But an empty ordered
>collection has no place at which to put them. :-)

You're absolutely right.

Travis Griggs has a fix in his Math For Engineers goodies
	<ftp://st.cs.uiuc.edu/Smalltalk/Squeak/goodies/EngineeringMath/EngineerMath.html>
and I have incorporated it in the latest Squeak updates (specifically ihn update #386).  Therefore it will be fixed in 2.3.

Thanks for the report.

	- Dan