Outlook Plugin Does Not Send New Calendar Appointments to Sugar

[Roobarb]

OS is Windows XP SP3
Outlook 2003
Sugar is Version CE 5.2.0.c
Sugar Outlook Plugin is V5.2
Apache 2.2.11
MYSQL V 5.0.75
PHP V5.2.9

New appointments made in Outlook are not appearing in Sugar. If I create an appointment in Sugar, it does sync into Outlook; if I then modify the appointment in Outlook, it syncs back to Sugar correctly. Only new Outlook appointments fail to sync.