SQL CLR UDF

[songstre]

am currently trying to write a very simple UDF that checks for the
existence of a file. If the file does not exist it should return
null.
It doesn't seem to see the file even when it exists, however. I've
checked and rechecked and the file is there. HELP!
I tried using both UNC and mapped drive.

[Microsoft.SqlSe rver.Server.Sql Function(DataAc cess =
DataAccessKind. Read, SystemDataAcces s = SystemDataAcces sKind.Read)]


[System.Security .Permissions.Pr incipalPermissi on(System.Secur ity.Permission
s.SecurityActio n.Demand)]
public static SqlString GetPictureUrl(s tring accountName)
{
try
{
if (accountName == null || accountName == string.Empty)
return SqlString.Null;
else if (System.IO.File .Exists(@"Y:\Hr \OurPeople\Whos Who
\photos\big\" + aname + ".jpg"))
return new SqlString("http ://mh000xsiis01/hr/
ourpeople/
whoswho/photos/big/" + aname + ".jpg");
else
return SqlString.Null;


}
catch (Exception exc)
{


throw exc;
}
}