Following errors can happen when any field in the database is attempted to insert or update larger data of the same type or other data type.
Msg 8115, LEVEL 16, State 2, Line 2 Arithmetic overflow error converting expression TO data type <ANY DataType>
Example is if integer 111111 is attempted to insert in TINYINT data type it will throw above error, as well as if integer 11111 is attempted to insert in VARCHAR(2) data type it will throw above error.
1) Verify the inserted/updated value that it is of correct length and data type.
2) If inserted/updated value are correct modify the definition of the table to accommodated new data type length.
Reference : Pinal Dave (http://blog.SQLAuthority.com)