Sims 3 Master Suite Stuff problems.

Hi, thank you so much for making this Stuff Pack available so quickly, it's really greatly appreciated.

However, I've been having a few problems since installing it! Played by the enclosed readme instructions, and got this message: "It looks like you have installed an unofficial game modification that
does not match your current version of The Sims 3. We recommend that you
either uninstall these game modifications or get updated versions of
them - otherwise you may experience crashes or significant bugs."

So, I temporarily removed all mods, deleted the cache etc. Then with the Pets expansion applied the Ultimate Fix (definitely followed all instructions, no problems there) and then the crack. It worked absolutely perfectly. Funny thing is, I've turned on my computer today (a day after I did this) and now I am getting the message that there is some custom content that is out of date and may cause bugs/crashes..

Could this be something to do with the game itself, or have I just done something wrong? I'm going to try and re-load the fix again, just incase I did it wrong- but if anyone could help, would be really grateful.

Oh p.s I am patched up to date.