It is very hard to tell from info that you provided.
But it looks like you are tryng to read first character of non-existing string.

Check your arrays and first letter reading parts.

Java Script
What am I doing wrong? Why are attempts failing?
Test Results:
Test Passed: Value == 'S.H'
Test Passed: Value == 'P.F'
Test Passed: Value == 'E.C'
Test Passed: Value == 'P.F'
Test Passed: Value == 'D.M'
TypeError: Cannot read property '0' of null
at abbrevName
at /home/codewarrior/index.js:18:19
at /home/codewarrior/index.js:50:5
at Object.handleError