Did you modify this code?
If you look at the errors it becomes relatively easy to know what is wrong.
"L 04/25/2019 - 1759: Invalid array handle provided (0)"
Line 36 error: There is a 1.5 second delay between plugin_init() and when the array handles are registered. Its likely that players are connecting within this 1.5 second window before the array handles get assigned.
"L 04/25/2019 - 1759: [MySQL] Invalid info tuple handle: 0"
Line 334 error: You are calling SQL_Connect() on a g_Tuple that is equal to 0. You must first call g_Tuple = SQL_MakeDbTuple( .. )