Error while creating a irule

I think some of the braces should be replaced by parentheses. Try this:

when HTTP_REQUEST { 
  if { ( [string tolower [HTTP::uri]] contains "/scjbos" ) || ( [string tolower [HTTP::uri]] contains "/biznc" ) } { 
    pool /Common/Bizagi_QA_SCJ_Pool 
    return 
  } else { 
    log local0. "packet discarded" 
    discard 
  } 
}