XML Entity not defined in Chrome

[Ari911]

My browser is telling me:\[code\]error on line 2 at column 308899: Entity 'ntilde' not defined\[/code\]and the specific line is in my xml as:\[code\]<LastName>Trevi&ntilde;o</LastName>\[/code\]the name was originally \[code\]Trevi?o\[/code\], but it was modified via php's \[code\]htmlentities\[/code\] function.What can I do to get php and xml to play nicely?Using Chrome 19 on Mac.