Mail Merge Weirdness

I have been trying to do a mail merge in Word 2010 with my xmas addresses in an Excel 2010 spreadsheet. It refuses to do more than 105 addresses. I recreated the spreadsheet and even reduced it to only the necessary fields (took out phone numbers etc.). I finally had to create a second spreadsheet for the balance of the addresses before I could get all the labels printed. Very strange.
I should say that Word 2010 is pretty easy to use and has a lot more power than older versions. I created the entire newsletter in no time with pictures and everything. Almost like they rolled all the stuff that used to be in Publisher into Word.