Bug4378370 test in libraries fails on Ladybird build 17 -RC1 Solaris5.6 and WinNT.

Steps to reproduce :
1)Go to Library workspace area i.e., testbase/src/setup
2)set PATH to build 17
3)set CLASSPATH to Tonga classes i.e., /net/sqesvr/export/xlt/libs/tonga/1.2/classes:.
4)To run the test type java Tonga -iniFile setup.ini.solaris
5)While running test Bug4378370 throws NullPointerException & fails.
when run individually it fails.

%java Bug4378370
Total tests for Exec : 1
Exception thrown = java.lang.NullPointerException
Bug4378370Test01() Fail
java.lang.NullPointerException
        at java.math.BigInteger.readObject(BigInteger.java:2966)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.io.ObjectInputStream.invokeObjectReader(ObjectInputStream.java:2214)
        at java.io.ObjectInputStream.inputObject(ObjectInputStream.java:1411)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:386)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:236)
        at TestClient.deserialize(TestClient.java:20)
        at TestClient.test(TestClient.java:9)
        at Bug4378370.Bug4378370Test01(Bug4378370.java:66)
        at Bug4378370.main(Bug4378370.java:29)
Pass count: 0
Fail count: 1
Test for Bug4378370.java Failed.

File attached to reproduce the bug are Bug4378370.java,TestClient.java,UnsignedInt64.java .