After you connect you need to create a new empty bug, then change its value, then post. The code in vbscript is below, you will need to something similiar in Perl.

'Create QTP Object
Set qtApp = CreateObject(''QuickTest.Application'')

'DisconnectTDConnection
qtApp.TDConnection.Disconnect

'Connect TDConnection
qtApp.TDConnection.Connect QCserver, QCdomain, QCproject, QCuser, QCpassword, False

'Set TDC Connection
Set tdc = qtApp.TDConnection.TDOTA
set BugFactory = tdc.BugFactory

'Add a new, empty defect
Set Bug = BugFactory.AddItem(Nothing)

'Enter required field values
Bug.Status = ''New''
Bug.Summary =''Your Summary Goes Here''
Bug.DetectedBy = ''YourName''
Bug.Post