Solution : https://service.sap.com/sap/support/notes/542918 (SAP Service marketplace login required)
Key words :
windows environment variable $temp, web application designer crashes, web application designer, individual program steps, program crashes, 'temp' directory, terms trace, crash reason, behaves incorrectly, 'trace' file
Related Notes :
542933 | Runtime error '429'.'ActiveX Component can't create object' |
533542 | WAD crash due to a corrupt workspace file |