@callumdOct 02.2007 — #This is an absolute guess..
Is it the operating system?
I know I had some trouble with some file names because one operating system on one server (I think it was Linux) was case sensitive, while Windows wasn't.
So the file:
pic1.PNG
Was not recognised on the Linux server if I referred to it as 'pic1.png', but Windows recognised it fine.
@rootOct 03.2007 — #Depends on the server, usually Apache server truncates at first white space, so ensuring that your white space is treated correctly in the first place will prevent this from happening.
As NightShift has suggested, urlencode whatever is causing the issue.