Slow Query Question/

I need to know the reasons why the below query is slow ..takes more than a min...I have total  4K records

<cfquery datasource="#attr.DSN#" name="SearchRes">
     select a.*, c.comments
     from ops$new.network_event a,
     ( SELECT  MAX( record_number ), comments, event_number
       FROM ops$new.ne_comment
     GROUP BY comments, event_number ) c
     where
      1 = 1
     <cfif attr.problem neq "" or attr.node neq "" or attr.lob neq "">
      And a.event_number in
      (
        select distinct e.event_number 
        from
         ops$new.network_event e
        , ops$new.ne_node n
        , ops$new.ne_problem p
        , ops$new.ne_lob l
        where
         1 = 1 And
         e.event_number = p.event_number
         and   e.event_number = n.event_number
         and   e.event_number = l.event_number
         <cfif attr.node neq "" and trim(attr.node) neq "All">
          And n.node in (#ListQualify(attr.node, "'")#)
         </cfif>
         <cfif attr.problem neq "">
          And p.problem_code in (#attr.problem#)
         </cfif>
         <cfif attr.lob neq "">
          And l.lob in (#ListQualify(attr.lob, "'")#)
         </cfif>
      )
     </cfif>
      And a.event_number = c.event_number(+)
      <cfif attr.tick neq "">
       And lower(TICKET_NUMBER) like lower('#attr.tick#%')
      </cfif>
      <cfif attr.status neq "">
       And status_code = #attr.status#
      </cfif>
      <!---StartDateTime--->
      <cfif attr.start_date0 neq "" and attr.start_date1 neq "">
       And Start_date between #CreateODBCDateTime(attr.start_date0)# And #CreateODBCDateTime(attr.start_date1)#
      <cfelseif attr.start_date0 neq "">
       And Start_date <= #CreateODBCDateTime(attr.start_date0)#
      <cfelseif attr.start_date1 neq "">
       And Start_date <= #CreateODBCDateTime(attr.start_date1)#     
      </cfif>

      <!---EndDateTime--->
      <cfif attr.end_date0 neq "" and attr.end_date1 neq "">
       And end_date between #CreateODBCDateTime(attr.end_date0)# And #CreateODBCDateTime(attr.end_date1)#
      <cfelseif attr.end_date0 neq "">
       And end_date <= #CreateODBCDateTime(attr.end_date0)#
      <cfelseif attr.end_date1 neq "">
       And end_date <= #CreateODBCDateTime(attr.end_date1)#     
      </cfif>    
     
      <cfif attr.division neq "" and trim(attr.division) neq "All">
       And lower(trim(division)) = lower('#trim(attr.division)#')
      </cfif>
      <cfif attr.hub neq "" and trim(attr.hub) neq "All">
       And trim(hub) = '#trim(attr.hub)#'
      </cfif>    
      <cfif attr.ack neq "" and attr.ack eq "Y">
       And ACKNOWLEDGE_EID is not null
      <cfelseif attr.ack neq "" and attr.ack eq "N">
       And ACKNOWLEDGE_EID is null
      </cfif>
           
      </cfquery>