I installed Pages version 5.1 in January, when I got the update notice, after upgrading to Maverick OS. But I had NOT noticed, until your latest post, that I also still have Pages version 4.1 on my computer. I erroneously "assumed" the 5.1 update would have overridden the 4.1 version. I suppose it didn't, because the 4.1 version was in my iwork 09 folder and the 5.1 is listed as a separate app. That might be yet another wrong assumption! Because I have them, I'll keep both versions, just in case I need it sometime in the future when working with documents created earlier.
That also explains why I keep getting queries, upon saving documents I have created, asking if I want to update it to the newer version. I thought it was odd, because I knew I had installed the latest version. The icons for both the 4.1 and 5.1 versions were on my dock! I must have mistakenly been using the older version. I have now removed the older version from the dock! I'll check to see if the same thing is true of numbers & keynote. I never use keynote, but I create lots of spreadsheets!
I thought the reason I couldn't send pages docs as attachments to my emails was because I was using the earlier pages version. So, I just tried to attach a document I created in Pages 5.1 to an email and got the same results as always, i.e., "FAILED". It must be in one of my settings. I checked for MAC settings that might be causing it, but couldn't find one that seemed to be the culprit. I'll check my G-mail settings, in case it's one of those settings. Now I'm thinking it must be there. If I don't have any luck, I guess I'll try another discussion forum. At least I think I now understand how to do that!
It's always been that way for my email attachments, since I bought the Snow Leopard in 2011, so I "assumed" it must be a compatibility issue between iMACs & PCs. It was annoying, but I figured most recipients have PC's anyway, so I was willing to do it. I'll keep looking, now that I know it doesn't have to be that way. It's like making my way through a never-ending maze! Again, thanks for the heads up!!