File save errors

[Anonymous]

What do the following errors mean when saving a master assembly. I was
editing sub assemblies and saved them ok but when it came to the main
assembly I received the following errors

[ERROR] Error(s) detected while writing segment AmDcSegment in database
(FILENAME) [r:\core\RSe\segment\segStream.cpp, line 242]
[ERROR] Error detected while saving object of type RDxOccurrence
[r:\core\RSe\meta\meta.cpp, line 967]
[ERROR] Internal error in persistence operation (Segment loading is
not supported within other persistence operations)

[ERROR] The database in (FILENAME) could not be saved
[r:\core\RSe\database\databaseC.cpp, line 1195]


Thanks
Rob