Solution : https://service.sap.com/sap/support/notes/1010878 (SAP Service marketplace login required)
Key words : 
terms ehs2005sp08dgpai flg_paipao flg_paopagw flg_pagwpasi flg_pasimulrq flg_mulrqrelq flg_relq reason, menu path 'goto -> text elements -> text symbols', menu path 'goto -> text elements -> selection texts', relq pai pao pasi pagq mulrq, relq pai pao pasi pagw, menu path 'goto -> documentation', flg_mulrq_forbid und flg_relq fields, excepted quantity outer packaging, excepted quantity gross weight, dangerous goods mastermaximum length
Related Notes : 
       
| 1235826 | A short dump occurs in the program DGP_CONV_VALUE_FLG | 
| 1157472 | FAQ: Dangerous goods problems after upgrade/EHS installation | 
| 1048850 | Missing values after you import a dangerous goods master |