Need help passing Array in Form

I need some help learning how to pass Arrays and Variables when my Form is submitted.

Initially when my Script/Form loads, I build two arrays like this…

	// Set Incoming Array Counter.
	$i = 1;

	// Fetch record.
	while (mysqli_stmt_fetch($stmt6)){
		// Build All Incoming Array.
		$allIncomingArray[$i] = $pmID;
		echo $allIncomingArray[$i] . '<br />';

		// Build Incoming Array.
		$incomingArray[$i] = array('pmID' => $pmID,
							'readOn' => $readOn,
							'flag' => $flag,
							'fromID' => $fromID,
							'fromUsername' => $fromUsername,
							'subject' => $subject,
							'sentOn' => $sentOn);
		$i = $i + 1;


(As you can see, I echoed the 1st array to the screen to confirm that it exists and has values.)

At the bottom of my script, I have my PHP/HTML which builds the Form like this…

	// ****************************
	// Create 'Incoming' Output.	*
	// ****************************
	echo "<h2>Incoming Messages</h2>
			<table border='1'  cellspacing='1'>
					<!-- Header Bar -->
						<td id='headerBar' colspan='5'>
							<!-- Message Actions -->
							<select name='pmAction'>
								<option value=''>For the selected...</option>
								<option value='In_Unread'>Mark as Unread</option>
								<option value='In_Read'>Mark as Read</option>

							<!-- Submit Button -->
							<input type='submit' name='submit' value='Go'/>

<!-- LOOK HERE -->
					<!-- Column Headings -->
						<th class='colSelect' />
							<input name='allIncomingArray[]' type='checkbox' value='TRUE' />
						<th id='colFlag'>
							<img src='/images/Flag_Red_20x22.png' width='15' alt='' />
						<th id='colFrom'>From</th>
						<th id='colSubject'>Subject</th>
						<th id='colDate'>Date</th>

(As you can see in this snippet, I am trying to pass the $allIncomingArray in the <input name=‘allIncomingArray[]’ line…)

And at the top of my script I have this code to handle the Form when it is submitted…

	// ****************************************************
	// HANDLE FORM.									 *
	// ****************************************************
		// Form was Submitted (Post).

		// ****************************
		// Check for Message Action.	*
		// ****************************
		if ($_POST['pmAction']=="In_Unread"){

			// **************************
			// Mark Incoming as Unread.	*
			// **************************
echo var_dump($_POST['allIncomingArray']);

foreach($allIncomingArray as $allKey => $allValue){
	echo '$allKey = ' . $allKey . ', $allValue = ' . $allValue . '<br />';

Here is the problem…

If I choose “Mark as Read” in my drop-down, and I check the Top Check-box in the “Select” column, and then I choose “Go”, I was expecting that my $allIncomingArray to get passed from my script in the $_POST array and end up being echoed to the screen as confirmation.

But instead, I get this…

0 => string ‘TRUE’ (length=4)

And if I just choose “Mark as Read” from my drop-down, but I do NOT check the Top Check-box, then I get this error…

Notice: Undefined index: allIncomingArray in /Users/user1/Documents/DEV/++htdocs/06_Debbie/account/messages.php on line 94
Call Stack
#	Time	Memory	Function	Location
1	0.0021	205724	{main}( )	../messages.php:0


Can someone help me figure this out?! :-/