I have successfully upgraded (test server) from 7.+ using tools provided with no problems. Everything is great but I have similar problems with uploading files.
Firstly for some reason the 'insert image' and 'File upload' buttons in the post forms do not work in IE 6 +. (No response other than IE 6 gives display 'error on page message' line 159 object expected on both post and edit forms)
Using Firefox (only tested using ASPupload) the upload window appears but it causes the page and the instance of Firefox to hang.
The RTE option is enabled, the forum upload permissions are correct, the folder permissions on the webserver are also correct.
I have tried this feature using ASPupload, Dundas, and ASPsmartUpload and have checked the configuration settings but am now stummped.