diff --git a/mozilla/netwerk/base/src/nsFileTransportService.cpp b/mozilla/netwerk/base/src/nsFileTransportService.cpp
index 900b74fe645..94717e1afb3 100644
--- a/mozilla/netwerk/base/src/nsFileTransportService.cpp
+++ b/mozilla/netwerk/base/src/nsFileTransportService.cpp
@@ -175,14 +175,14 @@ nsFileTransportService::DispatchRequest(nsIRunnable* runnable)
 nsresult 
 nsFileTransportService::AddSuspendedTransport(nsITransport* trans)
 {
-    mSuspendedTransportList.AppendElement(trans);
+    mSuspendedTransportList.AppendElement(NS_STATIC_CAST(nsISupports*, trans));
     return NS_OK;
 }
 
 nsresult 
 nsFileTransportService::RemoveSuspendedTransport(nsITransport* trans)
 {
-    mSuspendedTransportList.RemoveElement(trans);
+    mSuspendedTransportList.RemoveElement(NS_STATIC_CAST(nsISupports*, trans));
     return NS_OK;
 }