error in fax sending .net application and in fax console,exceptions as system.runtime.interopservices.com exception (0x80070102):operation failed

i have a fax sending application in vb.net and i was sending the fax through the fax console the fax console shows me that documents in it's queue are being sent when the service is started .but it send just one document when started.and doesn't sends the next document

but even though fax console shows that the second and third documents are being sent,

but the documents are still there except the first document which has originally been sent.

the log exception shows the following error

system.runtime.interopservices.com exception (0x80070102):operation failed.

when i analaysed for the exception,it is said that the "The semaphore is set and cannot be closed"

means that wait time out for a certain thread has elapsed

The question is why is the fax console showing that second and third documents are being sent with out actually sending them?.

why does the system.runtime.interopservices.com exception (0x80070102):operation failed. exception arises?

how to fix this issue of sending the first document but not the next subsequent documents?