Everyone here but one 'pro' said it'd be fine to run parallel. Against my gut, I followed this advice. I lapped the paper two inches.

*Every* single seam sticks up. It's not huge, but I can tell visually and if I put furniture there I'm sure it'll be unlevel.

What'd I do wrong and how can I correct this (I'm about 3/4 done).

What is that thickness of the flooring you are laying? I have always promoted #15 asphalt felt, never #30, be lapped by 4" , not 2", and only for unfinished solid 3/4" flooring that is to be sanded in place. For prefinished, I recommend butting the felt together, no overlap. OR, use a thinner paper, like Aquabar by Fortifiber. That's especially important for thinner nail downs and engineered floors. This is one of those instances where the installer is suppose to determine the correct product and outcome. Had you read more posts on this subject, you would have seen that no one recommends the same underlayment for EVERY floor. And I have always recommended following the manufacturer's installation instructions to the letter. What do they say to do? But what to do now? I can't imagine it's so bad that your furniture will wobble so that's not an issue. It's really more visual and if you will notice, you probably can only see it at certain angles with the lighting just so. So unless you wish to attempt to remove it, I'd leave it alone. If it's to be sanded, then you have no problem. It will sand flush. At this point, just butt the seams together and do not overlap. Was it difficult to install (engage T&G) where the felt overlapped? If so, that should have been an indicator that something was amiss. Read this post I made recently:

OR, if you prefer, this one:

Argh.

I'm probably the only new poster here who actually has read any and all previous posts here remotely related to their job. Somehow I missed the all-caps "PREFINISHED" part.

It wasn't too hard to get the pieces to fit at the seams.

Okay, it won't be that big of a deal to pull the rest of the paper and butt the seams together. Actually, I might just cut it in place and pull the strips out like you do with wall-paper.

Thanks, Gary.

Can you supply more information on why you use Aquabar by Fortifiber on prefinished flooring,I will be installing 3/4" prefinished flooring soon in my home. What is the size of Aquabar by Fortifiber, could not find this, as compared to the Rosin paper of 4' X 150"?

In my area, it has been used for many years. Keep in mind, it is NOT a vapor barrier. If your crawl space is damp with high humidity levels, nothing on the subfloor will prevent the wood flooring from water damage (cupping). Here is a link the manufacturer.
http://www.fortifiber.com/floor_protect ... nefits.htm
http://www.fortifiber.com/floor_protect ... _chart.htm

I butted the tar paper on my prefinished engineered and it looks and works fine.

That is what is recommended when using a thicker underlayment paper, like # 15 asphalt felt.