Can't format new defined partitions

[Oldsmobile_Mike]

Where can I download older WB versions?

Instead of going back, you should be going forward.  Upgrade to 3.1/3.9 for an easier experience.  Unless of course, you enjoy banging your head against the wall.  

[Oldsmobile_Mike]

I have a A500+ with the new ACA500plus and would like to prepare a 4gb CF and install games onto it.

Didn't this question already get answered elsewhere?  You shouldn't need any additional hardware to prep a CF card or copy files, with the new ACA500Plus.  I don't own one, but at least according to the product website everything you need to be able to do that is built-in.  

"The ACA500plus comes with essential software pre-installed in it's large flash. This includes fully licensed Kickstart versions V1.2 and V1.3 for backwards-compatibility, and Kickstart V3.1 for running the final version of the OS that Commodore has published. You've lost your installation disks of the OS? Not a problem with the ACA500plus. A full installer for OS3.1 is included in the product. All you need is an empty CF card, and you can install OS3.1 with a few key presses. After that's done, you can use the second CF card slot to exchange data with a modern PC: The ACA500plus supports PC-formatted cards and long filenames out of the box, no special installation required."

https://icomp.de/shop-icomp/en/produkt-details/product/ACA500plus.html

[Oldsmobile_Mike]

I know and it is easy to install a 4gb CF with the new ACA500plus, but how do I install WB Classic Lite and install all the WHDLoad games onto my CF?

I assume you're asking because your A500 doesn't have an Internet connection to download the installer?

you can use the second CF card slot to exchange data with a modern PC: The ACA500plus supports PC-formatted cards and long filenames out of the box, no special installation required."

So, download on your PC, transfer to your Amiga via the second CF slot, and done.

Although IMHO I would avoid "Classic Workbench". Makes the system too un-Amiga-like, in my opinion, and can cause other issues if you're unfamiliar with the exact nature of the changes. Check out "BetterWB" if you really want some kind of upgrade pack, instead.  My .02 cents.

[Oldsmobile_Mike]

What do you exactly mean by makes the system too un-Amiga like?

I mean they change the way basic tasks are performed in an unexpected  manner.  For example if on a regular Amiga you click 'x' to get 'y'  result, some of these enhancer packs change things around so you'll get  'z', instead.

Sometimes it's an improvement.

Other times it just frustrates the heck out of someone who's used to doing something the same way for 30 years and makes troubleshooting an absolute nightmare.  

If I install BetterWB, how do I install WHDLoad afterwards?

Download WHDLoad_usr_small.lha from the WHDLoad website.

[Oldsmobile_Mike]

I noticed that Opus on my A1200 looks different then on my Amiga 500. It seems that LHA extractor is integrated into Opus on my A1200 and not on my A500. Am I mistaking or is there a way to integrate LHA extractor into Opus?

All of these directory utilities are completely customizable.  I'm not familiar with the ins and outs of Dopus, but a quick google search for "amiga dopus manual" turns up a lot of links.  Maybe you can find one for whatever version you're using?