diff --git a/mozilla/netwerk/cache/src/nsMemoryCacheDevice.cpp b/mozilla/netwerk/cache/src/nsMemoryCacheDevice.cpp
index d4a7c876bfb..fb4d2f9958f 100644
--- a/mozilla/netwerk/cache/src/nsMemoryCacheDevice.cpp
+++ b/mozilla/netwerk/cache/src/nsMemoryCacheDevice.cpp
@@ -364,7 +364,7 @@ nsresult
 nsMemoryCacheDevice::EvictEntries(const char * clientID)
 {
     nsCacheEntry * entry;
-    PRUint32 prefixLength = nsCRT::strlen(clientID);
+    PRUint32 prefixLength = (clientID ? nsCRT::strlen(clientID) : 0);
 
     PRCList * elem = PR_LIST_HEAD(&mEvictionList);
     while (elem != &mEvictionList) {
diff --git a/mozilla/xpfe/components/prefwindow/resources/content/pref-cache.js b/mozilla/xpfe/components/prefwindow/resources/content/pref-cache.js
index 3a902f95c55..813f7ee2382 100644
--- a/mozilla/xpfe/components/prefwindow/resources/content/pref-cache.js
+++ b/mozilla/xpfe/components/prefwindow/resources/content/pref-cache.js
@@ -26,18 +26,17 @@ function prefCacheSelectFolder()
 
 function prefClearCache(aType)
 {
-  var cacheService = Components.classes['@mozilla.org/network/cache;1?name=manager']
-                               .getService(nsINetDataCacheManager);
-  cacheService.clear(aType);
+    var classID = Components.classes["@mozilla.org/network/cache-service;1"];
+    var cacheService = classID.getService(Components.interfaces.nsICacheService);
+    cacheService.evictEntries(aType);
 }
 
 function prefClearMemCache()
 {
-  prefClearCache(nsINetDataCacheManager.MEM_CACHE);
+    prefClearCache(Components.interfaces.nsICache.STORE_IN_MEMORY);
 }
 
 function prefClearDiskCache()
 {
-  prefClearCache(nsINetDataCacheManager.FILE_CACHE |
-                 nsINetDataCacheManager.FLAT_CACHE);
+    prefClearCache(Components.interfaces.nsICache.STORE_ON_DISK);
 }