found bug that disabled printing from root.

Marlin/cardreader.pde

@@ -192,13 +192,15 @@ void CardReader::openFile(char* name,bool read)
   char *fname=name;
   
   char *dirname_start,*dirname_end;
+  if(name[0]=='/')
+  {
     dirname_start=strchr(name,'/')+1;
-  while(dirname_start!=NULL)
+    while(dirname_start>0)
     {
       dirname_end=strchr(dirname_start,'/');
       //SERIAL_ECHO("start:");SERIAL_ECHOLN((int)(dirname_start-name));
       //SERIAL_ECHO("end  :");SERIAL_ECHOLN((int)(dirname_end-name));
-    if(dirname_end!=NULL && dirname_end>dirname_start)
+      if(dirname_end>0 && dirname_end>dirname_start)
       {
         char subdirname[13];
         strncpy(subdirname, dirname_start, dirname_end-dirname_start);
@@ -212,7 +214,7 @@ void CardReader::openFile(char* name,bool read)
           return;
         }
         else
-        SERIAL_ECHOLN("dive ok");
+          ;//SERIAL_ECHOLN("dive ok");
           
         curDir=&myDir; 
         dirname_start=dirname_end+1;
@@ -226,7 +228,7 @@ void CardReader::openFile(char* name,bool read)
       }
       
     }
- 
+  }
   if(read)
   {
     if (file.open(curDir, fname, O_READ)) 
@@ -242,7 +244,9 @@ void CardReader::openFile(char* name,bool read)
     }
     else
     {
-      SERIAL_PROTOCOLLNPGM("file.open failed");
+     SERIAL_PROTOCOLPGM("open failed, File: ");
+      SERIAL_PROTOCOL(fname);
+      SERIAL_PROTOCOLLNPGM(".");
     }
   }
   else