Fixed some debug message crashes.

diff --git a/files/dos_fs.c b/files/dos_fs.c
index 792663a..da174a7 100644
--- a/files/dos_fs.c
+++ b/files/dos_fs.c
@@ -904,7 +904,7 @@
     int tmplen, drive;
     UINT flags;
 
-    TRACE("%s\n", longpath);
+    TRACE("%s\n", debugstr_a(longpath));
 
     if (!longpath) {
       SetLastError(ERROR_INVALID_PARAMETER);
@@ -964,7 +964,7 @@
     }
 
     lstrcpynA ( shortpath, tmpshortpath, shortlen );
-    TRACE("returning %s\n", shortpath );
+    TRACE("returning %s\n", debugstr_a(shortpath) );
     tmplen = lstrlenA ( tmpshortpath );
     HeapFree ( GetProcessHeap(), 0, tmpshortpath );