diff --git a/mozilla/xpinstall/src/nsXPInstallManager.cpp b/mozilla/xpinstall/src/nsXPInstallManager.cpp
index d56af702015..c1e74b68181 100644
--- a/mozilla/xpinstall/src/nsXPInstallManager.cpp
+++ b/mozilla/xpinstall/src/nsXPInstallManager.cpp
@@ -813,7 +813,7 @@ nsXPInstallManager::LoadParams(PRUint32 aCount, const PRUnichar** aPackageList,
             paramBlock->SetString( i, aPackageList[i] );
     }
 
-    *aParams = paramBlock;
+    NS_IF_ADDREF(*aParams = paramBlock);
     return rv;
 }