My Date Gets Subtracted by 1

Hello  Asp.net
I have a hard problem to work with .
I have a asmx webservice running on a remote pc . Which gets data on a Pervasive Database..
 
I retrieve the data via datasets .
 
This is how i get the dates
 
ddlPeriodStart.Items.Add(LastChar + " - " + Convert.ToDateTime(set.Tables[0].Rows[0][col].ToString()).ToString("dd-MMM-yyyy") + " - " + Convert.ToDateTime(set.Tables[0].Rows[0]["PerEndThis" + LastChar].ToString()).ToString("dd-MMM-yyyy"));  
This work perfectly on my localdrive  displaying
 
01 - 01 Apr 2011 - 30 Apr 2011
 
But when i try it by my hosting company the dates get subtracted by 1
01 - 31 Mar 2011 - 29 Apr 2011
 
I dont know how this could happen ?
I have tried CultureInfo.IrevlaiantCulture
 
Any i ...