At Companies the kind of company is specified (e.g. Holdings, subsidiaries, private companies). Not every kind of company has the possibility of having a job order linked directly to them (e.g. it is impossible to bill a holding). When you click New Job order there is no option to select an existing company. The administrator edits the kind of company allowing to link a Job order to this kind.
Method
Go to Maintenance
Go to Tables.
Select table kind of company.
Select desired Kind.
Check:
Can have vacancies.Click [Save].