You may not be able to upload images yet as you are a new user, but can use an upload service like dropbox or google drive; uploading and sharing your .dyn file will be useful for others to help as well.
Also a link to the tutorial you are following would be of use!
@STEVEHATCHER Just had a look, and here are some relevant threads on achieving rotation of columns I found searching the forum:
It seems that columns rotation is based upon the value of the parameter “Cross-Section Rotation”. This parameter becomes available when a column’s “Column Style” is set to “Slanted - Angle Driven”.
To rotate the columns with Dynamo, first use the Element.SetParameterByName node to change the column’s style from “Vertical” to “Slanted - Angle Driven”. This parameter value is an enumeration, so the values are as follows:
1: Slanted - Angle Driven
2: Slanted - End Point Driven
You will notice the numerical values for these Column Styles correspond with the order they are listed in the drop down when selecting the value in Revit.
After you’ve used the Element.SetParameterByName node to change the selected column’s “Column Style” to “Slanted - Angle Driven” or 1, the columns will have the parameter Cross-Section Rotation, which you can then use to modify their rotation with the same Element.SetParameterByName node - in your attached example to 30 degrees. Once you have rotated the columns you can then set their parameter values for Column Style back to vertical.
@STEVEHATCHER yes it appears that method works with Architectural Column families, not with Structural Column families. The error you were given tells me that you are trying to run the graph with Structural Columns and not Architectural Columns. Try selecting one of the elements in Revit and seeing whether or not it is a Structural Column or an Architectural column (left shows architectural column returns the category “Columns” while a structural column returns the category “Structural Columns”):