Xpath match assertion

I'm attempting to create an xpath match assertion to verify the contents on of a particular node in a Webservice response. After "declaring" the XPath Expressions and entering the Expected Results, the following error is being returned.

RuntimeException:net.sf.saxon.trans.XPathExcetion:XPath syntax error at char 0 {}: Unexpected token "<eof>" in path expression.

Any thoughts on the issue?