May be you are not following correct procedure...
Try again....click on.....
http://services3.cic.gc.ca/ecas/ECAS.jsp
click continue at the bottom....
click continue again on next page after clicking on the check box....
Then on the next page....
1. select "Identification Type" as "immigration file number"
2. "Identification number" as your file number starting with "B....." without any space b/w B & the digits...make sure this is the file number that you got from CHC ND and not CIO
3. Fill your surname exactly as you have mentioned in your application... If not working, you may also try your complete name in different ways... you know better.
4. Fill DOB and place of birth.... thats all
If still you are not able to open it.... check on the copies of original application forms, that you have filled all those particulars correctly there. Maybe there is some mistake in their records and you are filling correct information on ecas page.