- Misspelling of Array key (case sensitive).
- If the variable comes from another script, check the script is 'include'd or 'require'd at least once;
- Did you really define/set the Array element?
- Did you unset the Array element somewhere before?
Wife: "I can't open the JAR.". Programmer: "Download and install JAVA."
Executes another PHP script strFILE in the middle of the current script where called as if all of them were a single script.
Use PDO and its prepared statement functionality.
Use Debug Checkpoints to measure execution times of your application code blocks with a detailed listing of time consumption, how much went where.