I can see a few potential problem causers.
The code looks old because it's using deprecated mysql functions instead of mysqli or PDO
The query has "LIKE BINARY" which depending on the schema might be causing a problem
The include files might be messing things up.
The $tblAdminFld looks to not be defined anywhere (in an include file?)
- this might cause the code to not set the cookie and send users to admin.php?e0x=1 (or maybe sign-in.php?e0x=1)
Likewise if the query fails
- this might send users to admin.php?e0x=1 (or maybe sign-in.php?e0x=1)
To narrow things down, try temporarily adding the var_dump lines
// For Debugging ONLY
// End debugging lines
........... //the rest of the file
Don't post any real names or passwords, just whether or not you see what you're expecting to see.
Once you find out, change it back ASAP