<p>I've been using Subversion for code control with TortoiseSVN to interface with the server for the past few months, and in general it's been going great!  However, occasionally my FoxPro IDE will change the case of a file extension without warning where "<em>program.prg</em>" becomes "<em>program.<strong>PRG</em></strong>")  TortoiseSVN apparently takes this to mean the first file was removed, becoming flagged as "missing" and the second name comes up as "non-versioned", wreaking havoc on my ability to track changes to the file.   I understand that Subversion has it origins in the case-sensitive world of *nix but, is there any way to control this behavior in either Subversion or TortoiseSVN to be file name case-insensitive when used with Windows?</p>

Unfortunately, Subversion is case-sensitive. This is due to the fact that files from Subversion can be checked out on both case-sensitive file systems (e.g., *nix) and case-insensitive file systems (e.g., Windows, Mac).
This pre-commit hook script
may help you avoid problems when you check in files. If it doesn't solve your problem, my best suggestion is to write a little script to make sure that all extensions are lowercase and run it every time before you check in/check out. It'll be a PITA, but maybe your best bet.