Royal Icing... What went wrong??

OK... so I've been doing all these cookies and using Royal Icing up the wazoo (is that even a word..lol) with pretty good results.  BUT... this past weekend, I made some patriotic cookies and the red just didn't want to dry.  And some of the other colors were pretty runny (too runny) and took way longer to dry as well.  So... I went searching and searching to see what I did wrong..  (the red did eventually dry on my non-patriotic cookies I have sitting on my counter... like 2 days later)

Seems as though I could have done several things wrong this time around and the humidity that reached our area recently didn't help either.  So, here's what I think I did:
- too much water (this happens when you let your kids add the water...)
- too much color (I didn't have the no-taste red either... so not only did it not dry completely before party, I think the red tasted awful...I hate that taste...but there were no complaints from the cookie eaters, I just don't like it)
- humidity
- think I overbeat the icing...this also happens when you're trying to do too much at one time and  your kids are 'trying' to help you  (Please note: these cookies were for a bbq we were going to, so the kids helping was ok this time around... I generally kick them out of the kitchen when I am prepping and decorating)
- the use of the Wilton brand meringue powder, it seems, could have something to do with it

Yes...I did all of those things.  No wonder I had runny icing that didn't want to dry!!  But, alas, the best part of it all is that it was a lesson learned and I got some pics of the cookies to use in my photo gallery of cookies.

Here are my cookies:

I also found some fellow 'cookie decorating' bloggers... here are some links in case you are interested.. I found some new ideas on how to make, store and thin:)

http://savannahsouthernbelle.blogspot.com/2012/01/menu-monday-cookies-and-royal-icing.html

http://www.sweetsugarbelle.com/blog/2011/03/coloring-and-preparing-royal-icing/

http://onetoughcookienyc.com/2010/12/give-it-a-shpritz/

I will be trying the Sweet Sugar Belle way of making, storing and thinning... and I gotta get another spray bottle...that seems like a great tip for thinning the icing to make it NOT too runny:)

Happy decorating!!