Guys,
The code crashed after 5 weeks (CPU time) with the following screen dump.
Its running dual simulations concurrently and one of them crashed. It seems that the simulation managed to continue after restart. Still, scary stuff :-) !!

Screen dump:
Forrtl: severe(30): open failure, unit 5, file C:Program FilesBOINCprojectsclimateprediction.netkko_100046956_0tmpsmallslst.cpdc
Image PC Routine Line Source
hadsm3se_4.12_win 004F5347 Unknown Unknown Unknown
hadsm3se_4.12_win 004E2652 Unknown Unknown Unknown
hadsm3se_4.12_win 004E1361 Unknown Unknown Unknown
hadsm3se_4.12_win 004E188C Unknown Unknown Unknown
hadsm3se_4.12_win 004C3B88 Unknown Unknown Unknown
hadsm3se_4.12_win 0043E130 _fieldop_ 195 fieldop1.f
hadsm3se_4.12_win 00401AF9 Unknown Unknown Unknown
hadsm3se_4.12_win 004018E2 Unknown Unknown Unknown
hadsm3se_4.12_win 0052C41B Unknown Unknown Unknown
kernel32.dll 7C816D4F Unknown Unknown Unknown