XPages - opening a custom control causes Lotus Notes client to crash

I'm using Lotus Notes 8.5.3 FP1 with the Extension Library. I have a custom control which causes the Lotus Notes client to crash each time I try to open that custom control in Domino Designer. Most custom controls and Xpages open without problems. How can I debug and solve this issue? I have already tried deinstalling and reinstalling the Extension Library but the problem remains. It's also not posssible to open XPages containing that custom control in a browser. This gives Error 500 HTTP Web Server: Command Not Handled Exception.

Started at: Tue May 06 13:13:23 2014
Ended   at: Tue May 06 13:13:41 2014
Time Spent: 00:00:18

Generated Messages:

   INFO (0): This NSD was generated due to a Domino shutdown hang.
         There will not be a FATAL thread.  Any processes/threads other than
         the main server thread and the server timeout thread which started
         this NSD should be examined to determine why they did not terminate
         when requested to do so.

   INFO (0): failed to match all of the Notes processes
   INFO (0): Directory Listing for Workspace Logs not generated (no such directory).
   INFO (0): No Directory Listings for FT (none were open).
   INFO (0): terminated process [nNOTESMM:  0e90]
   INFO (0): terminated process [ belnapi:  1054]
   INFO (0): terminated process [ belnapi:  01f0]
   INFO (0): terminated process [ nserver:  0b34]
   INFO (0): process [nSMDreal:  0d90] has already terminated
   INFO (0): Deleting pid.nbf
   WARNING (0): proc [nSMDreal:  0d90] terminated
   ERROR (44): unable to open file 'C:\Lotus\Domino\framework\rcp\rcplauncher.properties' - (2) No such file or directory
   ERROR (0): Couldn't open the rcplauncher.properties file using the path C:\Lotus\Domino\framework\rcp\rcplauncher.properties to locate the workspace directory.



Please send the following files:

NSD Log : D:\Lotus\Domino\data\IBM_TECHNICAL_SUPPORT\nsd_W32I_chprone2_2014_05_06@13_13_23.log

Solution

Thanks a lot for your replies. I solved this problem by opening the Custom Controls with Domino Designer 9 on another PC. Somehow some syntax errors had occurred in the code. After removing these and cleaning the project, I was able to again work normally with designer 8.5.3