diff --git a/src/tests/kits/support/bstring/StringAccessTest.cpp b/src/tests/kits/support/bstring/StringAccessTest.cpp
index 85cbf2828d..772e854b91 100644
--- a/src/tests/kits/support/bstring/StringAccessTest.cpp
+++ b/src/tests/kits/support/bstring/StringAccessTest.cpp
@@ -76,6 +76,15 @@ StringAccessTest::PerformTest(void)
 	strcat(ptr, "pippo");
 	emptylocked.UnlockBuffer();
 	CPPUNIT_ASSERT(strcmp(emptylocked.String(), "pippo") == 0);
+	
+	// LockBuffer(0) and UnlockBuffer(-1) on a zero lenght string
+#ifndef TEST_R5	
+	NextSubTest();
+	BString crashesR5;
+	ptr = crashesR5.LockBuffer(0);
+	crashesR5.UnlockBuffer(-1);
+	CPPUNIT_ASSERT(strcmp(crashesR5.String(), "") == 0);
+#endif
 }
 
 
diff --git a/src/tests/kits/support/bstring/StringReplaceTest.cpp b/src/tests/kits/support/bstring/StringReplaceTest.cpp
index c4d476d6d3..8dc4b4404e 100644
--- a/src/tests/kits/support/bstring/StringReplaceTest.cpp
+++ b/src/tests/kits/support/bstring/StringReplaceTest.cpp
@@ -203,13 +203,14 @@ StringReplaceTest::PerformTest(void)
 	delete str1;
 
 	//&IReplaceLast(const char*, const char*)
+#ifndef TEST_R5	
 	NextSubTest();
 	str1 = new BString("she sells sea shells on the SEashore");
 	str1->IReplaceLast("sea", "the");
 	CPPUNIT_ASSERT(strcmp(str1->String(),
 		"she sells sea shells on the theshore") == 0);
 	delete str1;
-
+#endif
 	NextSubTest();
 	str1 = new BString("she sells sea shells on the seashore");
 	str1->IReplaceLast("tex", "the");
@@ -252,12 +253,14 @@ StringReplaceTest::PerformTest(void)
 	CPPUNIT_ASSERT(strcmp(str1->String(), "ccccccccccccccc") == 0);
 	delete str1;
 	
+#ifndef TEST_R5
 	//ReplaceSet(const char*, const char*)
 	NextSubTest();
 	str1 = new BString("abcd abcd abcd");
 	str1->ReplaceSet("ad", "da");
 	CPPUNIT_ASSERT(strcmp(str1->String(), "dabcda dabcda dabcda") == 0);
 	delete str1;
+#endif
 }
 
 
diff --git a/src/tests/kits/support/bstring/StringSearchTest.cpp b/src/tests/kits/support/bstring/StringSearchTest.cpp
index 45f56bf3aa..851fc30d4b 100644
--- a/src/tests/kits/support/bstring/StringSearchTest.cpp
+++ b/src/tests/kits/support/bstring/StringSearchTest.cpp
@@ -407,12 +407,14 @@ StringSearchTest::PerformTest(void)
 	i = string1->IFindLast("st");
 	CPPUNIT_ASSERT(i == 16);
 	delete string1;
-	
+
+#ifndef TEST_R5	
 	NextSubTest();
 	string1 = new BString("laSt but NOT leaSt");
 	i = string1->IFindLast("ST");
 	CPPUNIT_ASSERT(i == 16);
 	delete string1;
+#endif
 	
 	NextSubTest();
 	string1 = new BString;
@@ -455,18 +457,20 @@ StringSearchTest::PerformTest(void)
 	delete string2;
 
 	//IFindLast(const char*, int32)
+//#ifndef TEST_R5
 	NextSubTest();
 	string1 = new BString("abc abc abc");
 	i = string1->IFindLast("abc", 9);
 	CPPUNIT_ASSERT(i == 4);
 	delete string1;
-	
+//#endif
+#ifndef TEST_R5	
 	NextSubTest();
 	string1 = new BString("ABc abC aBC");
 	i = string1->IFindLast("aBc", 9);
 	CPPUNIT_ASSERT(i == 4);
 	delete string1;
-	
+#endif	
 	NextSubTest();
 	string1 = new BString("abc abc abc");
 	i = string1->IFindLast("abc", -10);