It's the . in the macro expansion. That will stop it. Try this.

for i = 1 to 10
   objectproperty = "P" + transform(i)
   oObject.&objectproperty. = somevariable
next

>Is there a way to reference an object property indirectly? For example, suppose you have an object with properties
>

>oObject.P1 = 23
>oObject.P2 = 63
>oObject.P3 = 93
>

>
>Now we want to change these values in a for/next loop.
>

>for i = 1 to 10
>   objectproperty = "oObject.P" + transform(i)
>   &objectproperty = somevariable
>next
>

>
>The macro sub doesn't work in this case. I suppose because its on the wrong side of the equasion.
>Is there a way to do this?