Arnon, what version of sqlite3 is the Python linked with?  Try:

python3.4 -c "import sqlite3;print(sqlite3.sqlite_version)"

What kind of database access is happening in your program, i.e. strictly multi-read, one writer many reads, multiple-writers?

Also, regarding the workaround, if you do call sqlite3.connect in the main process, check that you keep a reference to it (by assigning the result to a variable) so that the open connection doesn't get garbage-collected.