VCard grayed out when attempting to import into Address Book
I am trying to import 6000 contacts saved in the vcard format on my desktop into Address Book ver 5.0.3. The file is 2.6 MB. It contains 11 custom fields, as well as the usual name, title, company, phone, address, and notes fields. When I click on "import" in Address Book, the vcard file, which I have named "Addresses," shows up in the list in the dialogue window but is grayed out. I exported the vcard from Palm Desktop ver 4.2.1.
Does anyone have an idea why the vcard would be grayed out? I have searched the forum and no one else seems to be experiencing the same problem. I can't imagine 2.6 MBs would be too large a file to import, so what else might be the issue? I am trying to do this on a Macbook Pro 2.53 Ghz Intel Core Duo running OS 10.6.8.
Thanks for your help.
MacBook Pro, Mac OS X (10.6.8), 2.53Ghz Core Duo 500 GB HD