I am very new to houdini. I am trying to paint attributes on some cubes ( as directed in the 2nd tutorial) but when I try a warning comes up that says “Cannot paint on SOP with dislplay flag when it has differant points or primitive count from the selected SOP. Turn off paint with display mode.” What does this mean and how do I fix it.

You have your Paint sop selected (it has a yellow border around it and you can see the paint tool in the viewport), but you have your Display flag set on a sop above the Paint sop.
This means you won't be able to see the results of your painting.

Data only flows down in a node network, so your paint tool is complaining that it can't show you what it is doing.

Put your display flag on the Paint sop or a node below it, and you'll be fine.

Thanks, but Im a little confused about what a display flag is.

I would suggest you first watch the videos from the Apprentice section. They explain a bit about the UI. For e.g. this one: http://www.sidefx.com/index.php?option=com_content&task=view&id=766&Itemid=241 [sidefx.com]

In houdini help have a look at http://www.sidefx.com/docs/houdini10.0/ref/panes/network [sidefx.com]