Using the latest SilverStripe gsoc branch SVN r36618, the first time I try importing a CSV file I get these errors:
Notice: Undefined variable: funcName in /var/www/silverstripe-gsoc/sapphire/core/control/Controller.php on line 54

Notice: Undefined variable: funcName in /var/www/silverstripe-gsoc/sapphire/core/control/Controller.php on line 88

Notice: Undefined variable: colCount in /var/www/silverstripe-gsoc/cms/code/Newsletter/RecipientImportField.php on line 133

Next after clicking "Confirm" to import the list, I get these errors:

Notice: Undefined index: Set in /var/www/silverstripe-gsoc/cms/code/Newsletter/RecipientImportField.php on line 220

FATAL ERROR: Missing argument 2 for Session::set(), called in /var/www/silverstripe-gsoc/cms/code/Newsletter/RecipientImportField.php on line 247 and defined
At line 17 in /var/www/silverstripe-gsoc/sapphire/core/Session.php

Here is a patch that fixes all of the above errors except the "Undefined index: Set" one (I don't know the proper way to fix that):
http://www.elijahlofgren.com/silverstripe/patches/Fix-some-Errors-when-importing-Recipients-to-Newsletter-Mailing-List-cms-gsoc-r36618.patch

After fixing those errors, I get a bunch more errors:

1. If I choose "FirstName", "Surname", and "Email" as the column types and hit "Confirm" I get these errors:
http://www.elijahlofgren.com/silverstripe/bugs/Errors-when-importing-Recipients-to-Newsletter-Mailing-List-with-columns.html

The main errors in the above are:
Notice: Undefined index: showtemplate in /var/www/silverstripe-gsoc/sapphire/core/SSViewer.php on line 317
...
FATAL ERROR: None of these templates can be found: GenericEmail.ss
At line 53 in /var/www/silverstripe-gsoc/sapphire/core/SSViewer.php

2. Not choosing any column types and hitting "Confirm" I get these errors:
http://www.elijahlofgren.com/silverstripe/bugs/Errors-when-importing-Recipients-to-Newsletter-Mailing-List-no-columns.html

It includes the same errors as above, but also has:
Notice: Undefined index: Email in /var/www/silverstripe-gsoc/cms/code/Newsletter/RecipientImportField.php on line 256

I don't know how to fix those errors, but I'm guessing one of you guys can. :)

Here is the CSV file I was testing with:
http://www.elijahlofgren.com/silverstripe/bugs/Errors-when-importing-Recipients-to-Newsletter-Mailing-List-test.csv

Probably irrelevant, but just in case ;)
Server: Apache/2.2.3 (Ubuntu) PHP/5.2.1
Browser: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.4) Gecko/20061201 Firefox/2.0.0.4 (Ubuntu-feisty)
SilverStripe Version: gsoc branch revision 36618

I hope this helps,

Elijah Lofgren

Fixed in sapphire gsoc r38503 and cms gsoc r38508. Importing newsletter recipients now works in FF2, IE7.

However, reloading the recipient list does not work in Safari 3, something in reloadRecipientsList() is not working. I'll need to look into fixing that.

Note, I did not fix the 'Undefined index: Set' error because it seems harmless and I didn't know the proper way to fix it.

Fixed in Safari 3 with r38533.

This bug should now be completely fixed. :)