Get Items from Sharepoint List - sharepoint-2010

Question

I'm trying to get items from a list in sharepoint but i have some problems, it's difficult to explain so look at the code :
try
{
using (System.IO.StreamWriter file = new System.IO.StreamWriter(#"C:\log\Steps_" + DateTime.Now.Day + "_at_" + DateTime.Now.Hour + "h" + DateTime.Now.Minute + ".txt", true))
{
if (SPSite.Exists(new Uri(Url)))
{
using (SPSite site = new SPSite(Url))
{
file.WriteLine("step 1 : " + DateTime.Now.Hour + "h" + DateTime.Now.Minute + " " + DateTime.Now.Second + "s " + DateTime.Now.Millisecond + "ms ");
SPList list = site.AllWebs[""].Lists["CrmInfo"];
file.WriteLine("step 2 : " + DateTime.Now.Hour + "h" + DateTime.Now.Minute + " " + DateTime.Now.Second + "s " + DateTime.Now.Millisecond + "ms ");
var items = list.GetItems();
file.WriteLine("step 3 : " + DateTime.Now.Hour + "h" + DateTime.Now.Minute + " " + DateTime.Now.Second + "s " + DateTime.Now.Millisecond + "ms ");
foreach (SPListItem item in list.Items)
{
if (item.Name.Equals("serverName"))
serverName = (string)item["Value"];
if (item.Name.Equals("orgName"))
orgName = (string)item["Value"];
if (item.Name.Equals("userName"))
userName = (string)item["Value"];
if (item.Name.Equals("userPassword"))
userPassword = (string)item["Value"];
if (item.Name.Equals("userDomain"))
userDomain = (string)item["Value"]; }
}
}
}
}
catch (Exception e)
{
using (System.IO.StreamWriter file = new System.IO.StreamWriter(#"C:\log\error_" + DateTime.Now.Day + "_at_" + DateTime.Now.Hour + "h" + DateTime.Now.Minute + ".txt", true))
{
file.WriteLine("An error occured on {0}th at {1}h{2}", DateTime.Now.Day, DateTime.Now.Hour, DateTime.Now.Minute);
file.WriteLine(e.Message);
}
}
Here is the problem : if i remove
using (System.IO.StreamWriter file = new System.IO.StreamWriter(#"C:\log\Steps_" + DateTime.Now.Day + "_at_" + DateTime.Now.Hour + "h" + DateTime.Now.Minute + ".txt", true))
(with all corresponding file.WriteLine ...) and i deploy my feature on sharepoint, i get a 500 internal server error. If i let it like that, it works but i want to remove that part.
Can someone tell me what's wrong ? I really don't understand ...
Thank you.
edit : If i remove all the file.WriteLine ... when i deploy, it creats a Steps_xxxx.txt file which is empty (logic) but it catch an exception :
The process cannot access the file 'C:\log\Steps_17_at_12h22.txt' because it is being used by another process. But i'm not using it anywhere else!
Edit : New Element, i get this in my logfile
An error occured on 20th at 11h3
The request channel timed out while waiting for a reply after 00:00:43.5159686. Increase the timeout value passed to the call to Request or increase the SendTimeout value on the Binding. The time allotted to this operation may have been a portion of a longer timeout.
System.TimeoutException: The HTTP request to 'http://localhost:32843/SecurityTokenServiceApplication/securitytoken.svc' has exceeded the allotted timeout of 00:01:00. The time allotted to this operation may have been a portion of a longer timeout. ---> System.Net.WebException: The operation has timed out
at System.Net.HttpWebRequest.GetResponse()
at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout)
--- End of inner exception stack trace ---
at System.ServiceModel.Channels.HttpChannelUtilities.ProcessGetResponseWebException(WebException webException, HttpWebRequest request, HttpAbortReason abortReason)
at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout)
at System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan timeout)
mscorlib
I searched a little bit an modify the client.config timeout (from 00:00:20 to 00:02:00) but still not working ...
In fact there is one question to resolve this problem :
Why can't i use a SPSite in my feature ?
I found a way to debug the code when launching the sharepoint Site (using Debug->Attach to process...) and i tried with this :
if (SPContext.Current.Site.RootWeb.Site!=null)
{
using (SPSite site = SPContext.Current.Site.RootWeb.Site)
{
My breakpoint is on this first line and SPContext.Current.Site.RootWeb.Site is null ... Don't understand why.
then in a log file that i created i see this :
Object reference not set to an instance of an object.