RTC client 4.0.3 crashes when Delivering a Change Set

Hi!
I have no idea what is causing this issue, so I will try to give as much information and background as possible.

I am using RTC client 4.0.3 (same version as the one installed on our server).
We are using RTC in our team to manage the source code for a project.
The process to make changes is:
- create a change set
- associate it to a work item
- request for a review
- once approved deliver the change set

I have been using it on my computer running Ubuntu OCDC 12.04 (IBM J9 VM build 2.4, JRE 1.6.0) with no problem.
I decided to upgrade to Ubuntu OCDC 14.04 (that comes with IBM J9 VM build 2.6, JRE 1.7.0).
I forgot that I had a couple of change sets waiting for approval but I still had a backup of the single files I modified (not the whole workspace directory).
So, after the upgrade I reinstalled the RTC 4.0.3 client and checked the status of my work items. Every time I tried to open the change set associated with the item window, the client would crash after a short while. I suspected the reason was that the client was looking for the changes in my local machine and could not find them.
Somehow, in the short period before the crashes, I managed to remove the not yet delivered change sets from the affected work items.
I experienced some crashes when accepting some unrelated change sets but other than that I thought I solved the problem.
I then used my backup to reapply the changes and asked again for a review.
I now have an approval but whenever I try to deliver the change set the client systematically crashes.

How can I fix this?
Is it an incompatibility problem between the 4.0.3 client and 14.04/newer java?
Or is it a problem because of the change sets I lost with the upgrade?

This is the error I get when I launch the client from a terminal, I can provide the dumped java files if needed:

Unhandled exceptionType=Segmentation error vmState=0x00000000J9Generic_Signal_Number=00000004 Signal_Number=0000000b Error_Value=00000000 Signal_Code=00000001Handler1=00007FDF509AAB40 Handler2=00007FDF50663FF0 InaccessibleAddress=0000000000000000RDI=0000000000000000 RSI=00007FDF4D1308E0 RAX=00007FDF4F3CCB30 RBX=0000000000000000RCX=0000000000000001 RDX=00007FDF5235E968 R8=0000000000000000 R9=00007FDF4C0A5310R10=00007FDF5153BC70 R11=00007FDF5153BD70 R12=0000000000000004 R13=0000000000000119R14=00007FDF50B123C0 R15=00007FDE6422FA2ARIP=00007FDE2FCBF2A1 GS=0000 FS=0000 RSP=00007FDF5153C090EFlags=0000000000210206 CS=0033 RBP=00007FDF4D1308E0 ERR=0000000000000004TRAPNO=000000000000000E OLDMASK=0000000000000000 CR2=0000000000000000xmm0 0000000000000000 (f: 0.000000, d: 0.000000e+00)xmm1 2424242424242424 (f: 606348352.000000, d: 1.385533e-134)xmm2 00007fdf4c698538 (f: 1281983744.000000, d: 6.946417e-310)xmm3 0000000000000000 (f: 0.000000, d: 0.000000e+00)xmm4 00000000ff000000 (f: 4278190080.000000, d: 2.113707e-314)xmm5 0000000000000000 (f: 0.000000, d: 0.000000e+00)xmm6 00007fdf5153c520 (f: 1364444416.000000, d: 6.946421e-310)xmm7 0000000000000004 (f: 4.000000, d: 1.976263e-323)xmm8 0000000000000000 (f: 0.000000, d: 0.000000e+00)xmm9 0000000000000000 (f: 0.000000, d: 0.000000e+00)xmm10 0000000000000000 (f: 0.000000, d: 0.000000e+00)xmm11 0000000000000000 (f: 0.000000, d: 0.000000e+00)xmm12 0000000000000000 (f: 0.000000, d: 0.000000e+00)xmm13 00000000437f0000 (f: 1132396544.000000, d: 5.594782e-315)xmm14 0000000037800000 (f: 931135488.000000, d: 4.600421e-315)xmm15 0000000000000000 (f: 0.000000, d: 0.000000e+00)Module=/usr/lib/x86_64-linux-gnu/libsoup-2.4.so.1Module_base_address=00007FDE2FC53000 Symbol=soup_session_feature_detachSymbol_address=00007FDE2FCBF290Target=2_40_20130114_134867 (Linux 3.13.0-30-generic)CPU=amd64 (8 logical CPUs) (0x3d47e8000 RAM)----------- Stack Backtrace -----------soup_session_feature_detach+0x11 (0x00007FDE2FCBF2A1 [libsoup-2.4.so.1+0x6c2a1])Java_org_eclipse_swt_internal_webkit_WebKitGTK__1soup_1session_1feature_1detach+0x7f (0x00007FDE6422FAA9 [libswt-webkit-gtk-4236.so+0x5aa9])(0x00007FDF509C0C05 [libj9vm24.so+0x2ac05])---------------------------------------JVMDUMP039I Processing dump event "gpf", detail "" at 2014/07/08 09:14:44 - please wait.JVMDUMP032I JVM requested System dump using '/home/giuliofi/core.20140708.091444.9738.0001.dmp' in response to an eventJVMPORT030W /proc/sys/kernel/core_pattern setting "|/usr/share/apport/apport %p %s %c %P" specifies that the core dump is to be piped to an external program.  Attempting to rename either core or core.16667.JVMDUMP010I System dump written to /home/giuliofi/core.20140708.091444.9738.0001.dmpJVMDUMP032I JVM requested Java dump using '/home/giuliofi/javacore.20140708.091444.9738.0002.txt' in response to an eventJVMDUMP010I Java dump written to /home/giuliofi/javacore.20140708.091444.9738.0002.txtJVMDUMP032I JVM requested Snap dump using '/home/giuliofi/Snap.20140708.091444.9738.0003.trc' in response to an eventJVMDUMP010I Snap dump written to /home/giuliofi/Snap.20140708.091444.9738.0003.trcJVMDUMP013I Processed dump event "gpf", detail "".