Solution : https://service.sap.com/sap/support/notes/663843 (SAP Service marketplace login required)
Key words : 
500 sap internal server error  error message, screen structure includedthe object references fields, dump occurs whenthe opportunity, thefollowing error message, object references fieldsstored, object referenceswas removed, goto transaction /nse38 2, screen structure &, tables crmc_layoutc andcrmc_fieldgrpc, local object
Related Notes : 
       
| 696262 | CRM 4.0 SP Stack 1/2004 (SAPKU40004): Release & Info. Note | 
| 677456 | SAPKU40003: Support Package 03 for CRM 4.0 |