I can upload CSV files of new participants into my database if I don't try to import fields as new attributes.

But, if I do try to create a new participant attribute, I run into the following issue. The end result is that the 'attribute_name' value is empty and is not included in the SQL INSERT statement, and thus the new record in the table can't be created (because the column 'defaultname' is required.)

If I try to add 2 new fields called "role" and "dateRegistered" with my participant import, when I press the "Continue" button, the page POSTs to the webserver the following info:

Page: http://survey.citiprogram.org/index.php?r=admin/participants/sa/uploadCSV
Form Data:
YII_CSRF_TOKEN=f729c9754ce6d61e62378faaf1ea556dfccc92dc&characterset=auto&separatorused=auto&fullfilepath=ujibb87d5x7surntjk4j&newarray%5Brole%5D=role&newarray%5BdateRegistered%5D=dateRegistered&overwrite=false&filterbea=accept

Then it sends the following command to MS SQL:

declare @p1 int
set @p1=NULL
exec sp_prepexec @p1 output,N'@P1 nvarchar(2),@P2 nvarchar(5)',N'INSERT INTO [participant_attribute_names] ([attribute_type], [visible]) VALUES (@P1, @P2)',N'TB',N'FALSE'
select @p1

However, this fails with the following SQL error:

Cannot insert the value NULL into column 'defaultname', table 'LIMESURVEY.dbo.participant_attribute_names'; column does not allow nulls. INSERT fails.

The LimeSurvey interface itself doesn't display the error, it just shows "Processing" with a spinning green ring forever. The error is viewable in the 500 response from the webserver (using Chrome's inspector or Firefox's Firebug) & also logged on the SQL server.