If a concept uses the ampersand character (&) in its C_FULLNAME and/or C_DIMCODE (such as "\test\Procedures\CPT\Emergoing Technology, Services & Procedures\"), then any query that directly selects that concept fails due to "An error has occured while trying to run the query. The cell's message could not be interpreted as valid XML." The same query initiated from the workbench client works as expected.

A cursory investigation shows that the web client does not send the Query to the i2b2 server, and the cause appears to be that the ampersand character "&" may not be properly encoded into "&" during XML creation, thereby creating an invalid XML string. Or, perhaps a second layer of encapsulation is required to properly represent the ampersand character. I suspect that this error may also occur if other fields (C_NAME, C_COMMENT, etc) contain the ampersand character, but this has not been verified.