I know this post is over a year old, but the same error has got me puzzled.
I'm using SSRS 2008.
I also get this error when using "No Color" in a conditional expression. That's what the property value is set to when first opened. I've got two textboxes, and I set each one to use each (non)color.
[rsInvalidColor] The value of the BackgroundColor property for the text box ‘Textbox57’ is “No Color”, which is not a valid BackgroundColor.
[rsInvalidColor] The value of the BackgroundColor property for the text box ‘Textbox58’ is “Transparent”, which is not a valid BackgroundColor.
Here's the expression I'm using:
Basically, if the report is at a Regional level, I want to color the text box Light Grey if the Grp1 field is populated. It works, even with the error. Is this one of those times where I ignore it and move on?