Error on importing test cases with custom field

[amirhb9472]

Hi,
I'm using TestLink 1.9.20 and when I want to import test cases which has custom fields (the custom field made, and assigned to the project), I get the error message:
"
Import TestCase data : <test case name> : ok
Import TestCase data : <test case name> : Value of Custom Field <custom field name> can not be imported because there is no Custom Field with this name and Available for Test Case on this Test Project
"

I tried to use the syntax in the "tl-file-formats.pdf" file, but it didn't work. I created a test case with custom field, and exported it. But when I try to import the exported file, I got the same message.

Thanks in advance.