RE: Coverite paint and Coverite fabric covering, what went wrong?
Have you contacted Coverite about this? There may be some differences that caused this.
Was it the 21st Century fabric that you painted? It is already painted and may use a different type of paint that allows one to use an iron without ruining the finish. It may have had to be prep'd before painting. Cleaned with alcohol or acetone, maybe. Coverite should be able answer this.
When you recover, use the plain Super Coverite that's unfinished. I've used that to good success a few times. I think you'll like it as well.
You could also try Sig Koverall. A little more effort but very nice stuff.
Good luck !!!