That is coursed by some patterns being made with EAs own tool. Those pattern need to be installed though the launcher, they can not be merged or installed though CC magic.
What you do is try to disable the latest patterns that you installed in CC magic until the patterns start working again.
hate to bring this back butttt my buddy is having this same issue and swears up and down her game was running 100% fine the past few days w/o any problem and no new CC or anything.
went to play and it was stuck on this error for forever, and just in sunset valley for some reason.
i googled up and down, left and right to no avail since i knew it'd most likely be a pattern issue since it normally is but she'd be using said pattern just fine up until recently. i think there was an accidental .s3pack > .package and merging issue since we can all do it sometimes but is there anything else that can be done perhaps?
Original TS4 Content Rebeagles
I know that sometimes when I install sims or houses via the launcher (I use CC Magic but I install all sims3packs thru launcher first) I can get the materializing material error because they came with a pattern or something similar. I now disable all sims and lots in CC Magic as well and never have that problem. I don't know if this helps in anyway in solving the issue but I guess it's something that can get overlooked.