Glad to hear it helped. Feel free to report back, I’d love to hear how it goes.
Hi,
I did a large migration about a year ago (20,000 total topics and replies). You will definitely have timeout problems with an import that large, what I did was import items separately like so: users first then forum 1 topics, forum 1 replies, forum 2 topics, forum 2 replies and so on.
Of course back then there wasn’t an importer and we had to rely on custom scripts for all of it. The script was also run outside of WordPress/bbPress in an effort to stop timeouts. We also ran post-meta separately and did not attempt to transfer passwords (this was a migration from DNN/Microsoft SQL server so it wasn’t possible to retain passwords).
I am happy to help with specific question, I do agree it is a timeout issue.