Did you see the Contact Tab beside Customer tab in that you can see the Contact Company and one more thing is no need to provide a value for the Priority.
Urjency+Impact= Priority -- It will be taken automatically.
Please make sure all the field info is correct and try once.
import triggers merge and i am not sure whether incident number generation logic is triggered on the merge event as well...as you know incident number field is not request id(1) field...in this case you may need to give series of incident number when you are trying to import.....
Perhaps what I'll say is stupid because I don't know ITSM 7.0, but is there Data Management Tool in 7.0?
I know that on 7.6.04 there is an excel file with which you can insert "old" incidents.
It's file "transactional-incident".
Perhaps you could use it anyway to see which are the mandatory data? But indeed "IncidentID" is one of those mandatory data.
Perhaps instead of injecting in HPD:Help Desk you should try "HPD:IncidentInterface_Create"?
In 7.6.04 sp2 "Contact Company" in form HPD:Help Desk has a label "Company*+" and has ID 100....082.
I will suggest to use SOAP UI tool to emulate a regression test case. We can do regression and load testing with this tool for free of cost.
All you need is to build the webservice for that respective form and consume through SOAP UI.
This SOAP UI tool can generate test cases. You can specify 100, 200, 1000 dependes on your need for the number fo records to be created at remedy.