Ok, I am adding some information to my situation. Stated in the first letter, I found this error message:

Naming conflict: block section_links has the same title with an existing block, online_users!

Well, I went and checked in the block folder and found that "blockname" is used twice. Please look at the two bolded sections and see if this is the problem or not,

This function below is found in the block_sections_link.php file.

function CourseBlock_section_links ($course) {
        if (isset($course->format)) {
            if ($course->format == 'topics') {
                $this->title = get_string('topics', 'block_section_links');
            } else if ($course->format == 'weeks') {
                $this->title = get_string('weeks', 'block_section_links');
            } else {
                $this->title = get_string('blockname', 'block_section_links');
            }

This function is found in the block_online_users.php

class CourseBlock_online_users extends MoodleBlock {
    function CourseBlock_online_users ($course) {
        $this->title = get_string('blockname','block_online_users');
        $this->content_type = BLOCK_TYPE_TEXT;
        $this->course = $course;
        $this->version = 2004052700;