ACCESS (adp) XP/2003 - SQL 2005 Express Backend + .NET (SQL DEAD LOCK)

I have inherited this app -
Access adp file runs on the network, calling machines run either Access XP or 2003.
Form is bound to a table in sql 2005 express.
I have added a stored procedure to the database to insert a new row in the table.
The error I get from the .net app is as follows...
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                Error in calling assembly Avon Master Pleat Pack, Version=1.0.0.1, Culture=neutral, PublicKeyToken=null.
      Occured in .Net SqlClient Data Provider.
      ________________________________________________________________________
      Transaction (Process ID 70) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
      
      Description: An unhandled exception occurred during execution.
      
      The exception was thrown due to the SQL Server returning a warning or error.
      Please review the stack trace for more information about the error and where it originated in the code.
      
      Exception Details: System.Data.SqlClient.SqlException: Transaction (Process ID 70) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
      
      Source Error:
       .Net SqlClient Data Provider
      
      Stack Trace:
         at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
         at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
         at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
         at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
         at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
         at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async)
         at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)
         at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
         at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
         at DAL.MeasurementHeadersHelper.SaveOLDMeasurementHeader(String BarcodeBegin, String BarcodeEnd) in C:\Projects\Custom Filter\Source Code\CustomFilterRespiratorDatabase.DAL\MeasurementHeadersHelper.cs:line 133
         at Avon_Master_Pleat_Pack.Form1.buttonAccept_Click(Object sender, EventArgs e) in C:\Projects\Custom Filter\Source Code\Avon Master Pleat Pack\Avon Master Pleat Pack\Form1.cs:line 273
      
      Additional SQL Server Information:
      ________________________________________________________________________
       Server Name:      CF-FS1\SQLEXPRESS
       Error Type:      50000
       Error Level:      13
       Error Code:      52
       Procedure Name:      InsertNewMeasurementHeader
       Line Number:      131
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WHen making the stored procedur call to the database in the .net application, the acces application is not (to my knowledge) connected to the table performing the insert on.