Below is the code i use for finding a record. I am getting the error "No value given for one or more required parameters". Please help.

PHP Code:
private void Find()
        {
        
            
// to find a record in the database that matches the search
            // either lastname, salesorder, systemId or activationkey can be used to find.
            // The user would clear all the fields and type in one or more of these feilds
            // The user clicks on find to find the record which matches the entered criteria.
            
if (this.integerTextBoxSystemID.Text !="" ||   
                
this.textboxLastName.Text !="" || 
                
integerTextBoxSalesOrderNumber.Text !="" || 
                
this.textBoxActivationKey.Text !=""
            {  
                try
                {
                    
string strFind;
                    
String strLastName "ContactLastName=" textboxLastName.Text " ";
                    
String strSalesOrder "SalesOrder=" integerTextBoxSalesOrderNumber.Text " ";
                    
String strSystemID   "SystemID=" integerTextBoxSystemID.Text " ";
                    
String strActivationKey "ActivationKey=" textBoxActivationKey.Text " ";
                    
                    
String strWhere =    ((textboxLastName.Text!="") ? strLastName " and " "" ) + 
                                        ((
integerTextBoxSalesOrderNumber.Text != "") ? (strSalesOrder " and ") : "") +
                                        ((
integerTextBoxSystemID.Text != "") ? strSystemID " and " "") +
                                        ((
textBoxActivationKey.Text != "") ? strActivationKey "") ;

                    
int nFindLocation strWhere.LastIndexOf("and");
                    if(
nFindLocation 0)
                    {
                        
strWhere =     strWhere.Substring(0,nFindLocation -2);
                    }
                    
strFind "select * from Customers where " strWhere;
                    
oleDbDataAdapter1.SelectCommand.CommandType CommandType.Text;
                    
oleDbDataAdapter1.SelectCommand.CommandText strFind;
                    if(
oleDbConnection1.State == ConnectionState.Open)
                    {
                        
this.oleDbDataAdapter1.SelectCommand.ExecuteReader();    

                    }

                    
                }
                catch (
Exception ex)
                {
                    
MessageBox.Show("Error finding the record:  "+ex.Message,"Find Error",MessageBoxButtons.OK,MessageBoxIcon.Information);
                }    
//try-catch    
            
}
        }