ognl表达式错误

2011-01-17 13:51:39,559 WARN [com.opensymphony.xwork2.ognl.OgnlValueStack] (http-0.0.0.0-8080-218) Error setting value
ognl.ExpressionSyntaxException: Malformed OGNL expression: amp;type [ognl.TokenMgrError: Lexical error at line 1, column 4. Encountered: ";" (59), after : ""]在什么情况下会发生这种错误？
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