Merging Data Sets problems

#1
I have run into some problems merging data sets. I merged two different SPSS files which contained survey data from identical surveys. I sorted ascending the ID's and added cases. However when I ran a frequency test for one of my key variables my data looked like this :
Any help would be greatly appreciated.

YARG B.10 Merged Incorrectly.PNG
 

Dason

Ambassador to the humans
#2
I don't use spss but it looks like in one case it's treating that id as numeric and as character in the other case.
 

Dason

Ambassador to the humans
#5
I mean the second set is sorted as 0, 1, 10, 2,... Which is pretty indicative of being treated as character at some point.