Sql-server – Error when creating an index in SQL Server 2012

I'm trying to create the following index on our test environment (SQL Server 2012):

CREATE NONCLUSTERED INDEX [iTransaction-OriginatingTransaction] ON [dbo].[Transaction]
(
    [OriginatingTransactionID_EOT] ASC,
    [OriginatingTransactionID] ASC
)

on our transaction table:

CREATE TABLE [dbo].[Transaction](
    [TransactionID] [int] IDENTITY(1,1) NOT NULL,
    [OriginatingTransactionID_EOT] [varchar](50) NULL,
    [OriginatingTransactionID] [int] NULL,
    [Status] [int] NOT NULL,
    [BusinessID] [int] NOT NULL,
    [CreatedUserID] [int] NOT NULL,
    [CreatedDateTime] [datetime] NOT NULL,
    [ModifiedUserID] [int] NOT NULL,
    [ModifiedDateTime] [datetime] NOT NULL,
 CONSTRAINT [PK_Transaction] PRIMARY KEY CLUSTERED 
(
    [TransactionID] ASC
)

I get the following error:

Msg 681, Level 16, State 3, Line 2
Attempting to set a non-NULL-able column's value to NULL.

If I run the same create index statement on our live database (SQL Server 2005) then it works without any errors.

Why can't I create this index on SQL Server 2012?

UPDATE: Results of dbcc checktable:

Msg 8944, Level 16, State 13, Line 1
Table error: Object ID 954995248, index ID 1, partition ID 72057594796965888, alloc unit ID 72057595543093248 (type In-row data), page (1:701352), row 13. Test (ColumnOffsets <= (nextRec – pRec)) failed. Values are 7198 and 186.
Msg 8944, Level 16, State 13, Line 1
Table error: Object ID 954995248, index ID 1, partition ID 72057594796965888, alloc unit ID 72057595543093248 (type In-row data), page (1:701352), row 13. Test (ColumnOffsets <= (nextRec – pRec)) failed. Values are 7198 and 186.
Msg 8928, Level 16, State 1, Line 1
Object ID 954995248, index ID 1, partition ID 72057594796965888, alloc unit ID 72057595543093248 (type In-row data): Page (1:701352) could not be processed. See other errors for details.
Msg 8976, Level 16, State 1, Line 1
Table error: Object ID 954995248, index ID 1, partition ID 72057594796965888, alloc unit ID 72057595543093248 (type In-row data). Page (1:701352) was not seen in the scan although its parent (1:709848) and previous (1:700903) refer to it. Check any previous errors.
Msg 8978, Level 16, State 1, Line 1
Table error: Object ID 954995248, index ID 1, partition ID 72057594796965888, alloc unit ID 72057595543093248 (type In-row data). Page (1:701353) is missing a reference from previous page (1:701352). Possible chain linkage problem.
DBCC results for 'Transaction'.
There are 2354636 rows in 57941 pages for object "Transaction".
CHECKTABLE found 0 allocation errors and 5 consistency errors in table 'Transaction' (object ID 954995248).
repair_allow_data_loss is the minimum repair level for the errors found by DBCC CHECKTABLE (Redebiz.dbo.Transaction).
DBCC execution completed. If DBCC printed error messages, contact your system administrator.