[development] authentication hooks - PLEASE HELP

[Sheryl (Permutations Software)]

>> Strong PHP programmers will not stay dead in the water with an error
message saying "warning: Cannot modify header information - headers
already sent". It is easy to say that Drupal is so complicated, but
regardless of the application size, these are the easiest errors to
track, as they have the line number printed, where you can directly find
the unwanted output printed.

The lines causing the problems are echo statements that I put in there to
trace execution. Apparently you can't read.

If someone can offer helpful information, I will be VERY GRATEFUL. But
please don't waste time and bandwidth just to tell me I'm in idiot. Thank
you.