Nothing is obviously wrong, although I'm rather appalled at the style attribute value. Something that complex deserves its own class definition. And while I THINK css is case-insensitive, the convention is to use lower-case names for the style elements.
But as for your REAL problem, all I can say is "check the return value from the bean's property accessor and make sure its signature is as follows:
An IDE is no substitute for an Intelligent Developer.
subject: disabled attribute not rendered in commandButton