WebOPAC error

A WebOPAC problem occurred. Please inform the administrator.

WebOPAC error details

A potentially dangerous Request.Path value was detected from the client (&).

Message:
A potentially dangerous Request.Path value was detected from the client (&).

Stack trace:
at System.Web.HttpRequest.ValidateInputIfRequiredByConfig()
at System.Web.HttpApplication.PipelineStepManager.ValidateHelper(HttpContext context)

--------------------------------------------------