Okay here is all the code and i have put //****-> above the rows where i think ihave doen it right.
First is the Company cs file.
Second is the business rules file.

Thanks All in advance for help debugging.

using System;
using System.Data;
using OakLeaf.MM.Main.Business;
using OakLeaf.MM.Main.Data;
using OakLeaf.MM.Main;


namespace Apps4u.WinApp.Business.Company
{
	/// <summary>
	/// Main Company business object
	/// </summary>
	public class Company : OakLeaf.MM.Main.Business.mmBusinessObject
	{
		public Company()
		{
			///
			/// Required for Windows.Forms Class Composition Designer support
			///
			this.TableName = "company";
			this.PrimaryKey = "companyID";
			this.DatabaseKey = mmAppBase.AppSettingsMgr.GetSetting("SecurityDatabaseKey");
			this.DescriptionFields = new string[] {"CompanyUserID","CompanyName"};
			this.RetrieveAutoIncrementPK = true;
		}

		public DataSet GetAllCompanies()
		{	
			return this.GetDataSet("GetAllCompanies", "Company", this.DatabaseKey, CommandType.StoredProcedure);
		}
//****->
//****->
		public DataSet CheckIfCompanyUserIdExists(string CompanyUserID)
		{
			// Get a reference to the data access object
			mmDataAccessBase dao = this.GetDataAccessObject();

			// Create and configure two parameter objects
			IDbDataParameter sqlparCompanyUserID = dao.CreateParameter("@CompanyUserID",CompanyUserID);

			return this.GetDataSet("CheckIfCompanyUserIDExists","CompanyExists",this.DatabaseKey,CommandType.StoredProcedure,sqlparCompanyUserID);
		}
//****->
//****->
		/// <summary>
		/// Creates a business rule object
		/// </summary>
		/// <returns>Reference to the business rule object</returns>
		protected override mmBusinessRule CreateBusinessRuleObject()
		{
			return new CompanyRules(this);
		}
	}
}

using System;
using System.Data;
using OakLeaf.MM.Main;
using OakLeaf.MM.Main.Business;

namespace Apps4u.WinApp.Business.Company
{
	/// <summary>
	/// Summary description for CompanyRules.
	/// </summary>
	public class CompanyRules : OakLeaf.MM.Main.Business.mmBusinessRule
	{
		//public DataSet ds;
//****->
		public Company oCompany;
//****->

		public CompanyRules(ImmBusinessRuleHost hostObject) : base(hostObject)
		{
		}

		/// <summary>
		/// Checks business rules against the specified DataTable
		/// </summary>
		/// <param name="ds">DataSet</param>
		/// <param name="tableName">Table Name</param>
		/// <returns>Logical true if rules passed, otherwise false</returns>
		public override bool CheckRulesHook(DataSet ds, string tableName)
		{
			if (ds != null)
			{
				string CompanyUserIdEmpty;
				
				DataRow dr = this.DataRow;
				CompanyUserIdEmpty = this.ValidateEmptyCompanyUserID(dr["CompanyUserID"].ToString());
				this.ValidateEmptyCompanyName(dr["companyname"].ToString());
				// if the company user id has been filled in the we will 
				// run this process otherwise no point was server time.
				if (mmString.Empty(CompanyUserIdEmpty))
				{
					this.ValidateCompanyUserIDExists(dr["CompanyUserID"].ToString());
				}

			}

			return this.ErrorProviderBrokenRuleCount == 0;
		}

		/// <summary>
		/// Validate the Company User Defined ID
		/// </summary>
		/// <param name="CompanyUserID"></param>
		/// <returns>Empty Message or Failed Message</returns>
		public string ValidateEmptyCompanyUserID(string CompanyUserID)
		{
			string Message = null;
			if (mmString.Empty(CompanyUserID))
			{
				Message = "The Company User Id Field must have a value";
				this.AddErrorProviderBrokenRule("CompanyUserID",Message);
			}
			return Message;
		}

		/// <summary>
		/// Validate the Company Name
		/// </summary>
		/// <param name="CompanyName"></param>
		/// <returns>Empty Message or Failed Message</returns>
		public string ValidateEmptyCompanyName(string CompanyName)
		{
			string Message = null;
			if (mmString.Empty(CompanyName))
			{
				Message = "The Company Name Field must have a value";
				this.AddErrorProviderBrokenRule("CompanyName",Message);
			}
			return Message;
		}

		/// <summary>
		/// Validate the Company User Defined ID does not exist in the database
		/// </summary>
		/// <param name="CompanyUserID"></param>
		/// <returns>Empty Message or Failed Message</returns>
		public string ValidateCompanyUserIDExists(string CompanyUserID)
		{
			string Message = null;
			DataSet ds = null;
//****->	
			ds = this.oCompany.CheckIfCompanyUserIdExists(CompanyUserID);
//****->
			if (int.Parse(ds.Tables["CompanyExists"].Rows[0].ToString()) != 0)
			{
				Message = "The Company User ID already exists in the database please selct another Company User ID";
				this.AddErrorProviderBrokenRule("Company User ID",Message);
			}
			return Message;
		}
	}
}