Error on confirm page

This website was working fin then i changed something and i got this error then i changed it back and still got this error:

Parse error: syntax error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING in /home/goldne5/public_html/confirm.php on line 301

In the store order summary table i had this variable for for Order ID $_SESSION["eCart1_OrderID"] and my page worked then I changed something and now the page doesnt work and now i have to remove that variable and leave the spot blank and my page will work but my download page no longer works because i am going to sell digital files
here is line 301:

$WA_fieldValuesStr = WA_eCDB_ConvertNumber("$_SESSION[\"eCart1_OrderID\"]") . "|" . "".session_id() ."" . "|" . WA_eCDB_ConvertNumber("".$eCart1->GrandTotal() ."");

line 301 should be:

$WA_fieldValuesStr = WA_eCDB_ConvertNumber($_SESSION['eCart1_OrderID]') . "|" . "".session_id()  ."" . "|" . WA_eCDB_ConvertNumber("".$eCart1->GrandTotal()  ."");

Didn't work. the server behavior disappeared. This is from the backup file i created of the website folder. This site worked 2 days ago when i tested it and i made no changes to this file. But for some reason it does not work now.
The orderID field in the store order summary table had this variable: $_SESSION["eCart1_OrderID"] and this worked i was able to buy something then it would take me to a download page to download the file. I don't know why it doesnt work now. Once i got the site to work i copied the whole site folder to make a backup of it. And today when i couldnt get the site to work i deleted my website from the web server and uploaded the backup folder of the website that was working And i get this error message for some reason:

Parse error: syntax error, unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING in /home/goldne5/public_html/confirm.php on line 301

This is line 301 from the confirm.php page

$WA_fieldValuesStr = WA_eCDB_ConvertNumber("$_SESSION[\"eCart1_OrderID\"]") . "|" . "".session_id() ."" . "|" . WA_eCDB_ConvertNumber("".$eCart1->GrandTotal() ."");

I think that I may be working on you with this issue in a ticket, if so there is no need to respond to this thread. If not, please explain a little more about the problem you are experiencing and what you have updated the code to be like. The code that you posted in your last example might produce the same error you were having earlier, you should use the code example that Jason posted to get past this error.