DotNetZip FileIOPermission - can't add files to zip, though I have rights - asp.net

Question

I completely fail to get dotnetzip to add files to a .zip file
i can:
using (ZipFile zip = new ZipFile())
{
zip.AddEntry("test.txt", DateTime.Now.ToString());
zip.Save(Response.OutputStream);
}
This is completed correctly and produces a zip file for download that can be opned with the text file inside
Problem: Trying to add files like this:
zip.AddFile(Server.MapPath("/Files/test.txt"), "Files");
Always result in something like this:
[SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.]
System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) +0
System.Security.CodeAccessPermission.Demand() +61
System.IO.File.GetLastWriteTimeUtc(String path) +114
System.IO.File.GetLastWriteTime(String path) +24
Ionic.Zip.ZipEntry.Create(String nameInArchive, ZipEntrySource source, Object arg1, Object arg2) in c:\DotNetZip\Zip\ZipEntry.cs:2405
Ionic.Zip.ZipEntry.CreateFromFile(String filename, String nameInArchive) in c:\DotNetZip\Zip\ZipEntry.cs:2313
Ionic.Zip.ZipFile.AddFile(String fileName, String directoryPathInArchive) in c:\DotNetZip\Zip\ZipFile.AddUpdate.cs:406
Ionic.Zip.ZipFile.AddFile(String fileName) in c:\DotNetZip\Zip\ZipFile.AddUpdate.cs:296
MultiFileDownloader.WebForm1.Button1_Click(Object sender, EventArgs e) in D:\WORK\dynamicweb\StandardModules\MultiFileDownloader\Source\MultiFileDownloader\WebForm1.aspx.cs:54
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +111
System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +110
System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +6785
System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +242
System.Web.UI.Page.ProcessRequest() +80
System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +21
System.Web.UI.Page.ProcessRequest(HttpContext context) +49
ASP.webform1_aspx.ProcessRequest(HttpContext context) in c:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\ade7bc1a\c2b11481\App_Web_txhzteca.0.cs:0
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +181
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75
Note: My code can read/create the files with no problem. IIS user (and everyone infact) have total permissions to the files in question. IIS 7.5, win2008r2
How can I grant the DotNetZip assembly the same rights?

Answer 1

Figured it out my self:
On application pool I set the Load User profile to true....problem solved. Guess the assembly was running without any user at all (not everyone, not anomnynous, not no one)