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:

Char         Code 

[space]      20      i.e. _x0020_
<            3C      i.e. _x003c_
>            3E
#            23
%            25
{            7B
}            7D
|            7C
\            5C
^            5E
~            7E
[            5B
]            5D
`            60
;            3B
/            2F
?            3F
:            3A
@            40
=            3D
&            26
$            24

To reference a column called “e-mail” you would need e_x002d_mail.