What is the error below, i cannot use it ? The result is blank page! Thanks!

 <form name="search" method="post" action="search.php">
 Seach for: <input type="text" name="find" /> in 
 <Select NAME="field">
 <Option VALUE="fname">First Name</option>
 <Option VALUE="lname">Last Name</option>
 <Option VALUE="info">Profile</option>
 <input type="hidden" name="searching" value="yes" />
 <input type="submit" name="search" value="Search" />

 //This is only displayed if they have submitted the form 
 if ($searching =="yes") 
 echo "<h2>Results</h2><p>"; 
 //If they did not enter a search term we give them an error 
 if ($find == "") 
 echo "<p>You forgot to enter a search term"; 
 // Otherwise we connect to our Database 
 mysql_connect("mysql.yourhost.com", "user_name", "password") or die(mysql_error()); 
 mysql_select_db("database_name") or die(mysql_error()); 
 // We preform a bit of filtering 
 $find = strtoupper($find); 
 $find = strip_tags($find); 
 $find = trim ($find); 
 //Now we search for our search term, in the field the user specified 
 $data = mysql_query("SELECT * FROM users WHERE upper($field) LIKE'%$find%'"); 
 //And we display the results 
 while($result = mysql_fetch_array( $data )) 
 echo $result['fname']; 
 echo " "; 
 echo $result['lname']; 
 echo "<br>"; 
 echo $result['info']; 
 echo "<br>"; 
 echo "<br>"; 
 //This counts the number or results - and if there wasn't any it gives them a little message explaining that 
 if ($anymatches == 0) 
 echo "Sorry, but we can not find an entry to match your query<br><br>"; 
 //And we remind them what they searched for 
 echo "<b>Searched For:</b> " .$find; 

For starters, you still haven't defined your post variables yet.

How to define ? Thanks!