The max number allowed for a bigint column is 9,223,372,036,854,775,807, which you are reaching with the third insert.
One option could be changing the datatype of the column, as you suggested.
<pre>ALTER TABLE SubscriptionTrans
ALTER COLUMN transid NUMERIC(25)</pre>
But even the numeric and decimal datatypes have a limit in the amount of digits they can store (which is 38).
The value range of a bigint in SQL Server 2008 is:
bigint -2^63 (-9,223,372,036,854,775,808) to 2^63-1 (9,223,372,036,854,775,807) 8 Bytes
Your third insert exceeded the maximum storage value.