When referencing columns programatically or in CAML that have a space in the name replace the spaces with _x0020_
For example "End Use" becomes "End_x0020_Use"
The format required to access non-alphanumeric column titles is this (IN LOWER CASE):
_x00[the hex code]_
Here are a few more examples:
[space] 20 i.e. _x0020_
< 3C i.e. _x003c_
To reference a column called “e-mail” you would need e_x002d_mail.
This page has a list of all the Hex Codes of some other symbols:http://www.asciitable.com/