Error: Improper Statement

Error: Improper Statement

My Code:

htmlpage Frame(Display_Booking)
displayname = "EmbeddedView"
content
<%{%>    <div elName='zc-component' formLinkName='Display' 
  params='zc_Header=false&amp;zc_SuccMsg=Data Added Successfully!&amp;zc_SubmitVal=Submit&amp;zc_ResetVal=Reset&amp;Display_Booking=<%=Display_Booking%>' >Loading Form...</div> 
   <div elName='zc-component' viewLinkName='Booking_Summary_Report' params='zc_Header=true&amp;ID=<%=Display_Booking%>'></div>
   <%
   Userselectedid = input.Display_Booking.toLong();
   if (Userselectedid  == "")
     {
   openURL("https://app.zohocreator.com/anansrivastava/hotel-management/#Page:Frame?Display_Booking=3246746000000123009", "Same Window")
     }
%>
<%}%>

Says improper statement on the underlined line. Display_Booking is a lookup from a single line field from another form. The error message does not tell what the error is. Kindly check out the code and help me with this issue.