I am also using a Synway SHT-8B/PCI CAHTA card with IVM v5.10 (also tried IVM v4.08) where it will not answer any call.
The IVM log shows all these events at the same time (in this instance all @ 14:22:20):
14:22:20 Ringing on Line CAHTA 0 detected. Waiting until ring number 2.
14:22:20 CAHTA 0 [Answered].
14:22:20 Answered line [1 "CAHTA 0"] call number [16] cid[] did [CAHTA 0] drn[0 {2954ms}]
14:22:20 Play file: C:\Documents and Settings\All Users\Application Data\NCH Swift Sound\IVM\OGMs\Default Answering Message.wav
14:22:20 Call disconnected
On the phone making the call you only hear a ringing tone.
Any suggestions?
TIA,
Mark