It may help to take a step back and connect the qSIListView to a sample Oracle Database first, get it working and then tackle the Oracle instance that you are after. I created two short videos that show how to connect to Oracle Database 10g Express Release 2:
Part 1:
http://screencast.com/t/NTU4ZGEy
Part 2:
http://screencast.com/t/YzY3MTk1Zj
The example uses the same connection string that mentioned. As a test, download and install Oracle Express and follow the videos to get it connected. Once you verified that the qSIListView works with Oracle Express, download and install the Oracle Express Client:
http://www.oracle.com/technology/software/products/database/xe/htdocs/102xewinsoft.html
You should be able to connect to your Oracle system using the Oracle Express Client tools like TNSPING:
http://www.geekinterview.com/question_details/29370
If you can connect with the Oracle Express Client tool by adding your SID to the tnsnames.ora file, the client connectivity test will eliminate the firewall issue and your issue will be isolated to a problem with the connection string.
If this approach does not work, let me know. I've worked with Java and windows connections strings to Oracle in the past and we can setup a live meeting to resolve the issue. I think you will find resolving this issue worth the time and effort. Once the connectivity issue is resolved (it could be as simple as an extract comma in the connection string) the Quest SI web parts will impress you with their capabilities.
Curtis Kelly
PM, Quest WebParts for SharePoint