Render Studio Modular 1-4 + Scenes Install ERROR
I get this error when attempting to install "Render Studio Modular 1-4 + Scenes for Poser 4-Hollywood PS Action" I do not have PhotoShop or Poser. ny help would be appreciated. Pretty expensive add on.
Install Manager cannot find a required path. The package for "Render Studio Modular 1-4 + Scenes for Poser 4-Hollywood PS Action" requires that the installed path for "Photoshop CC, CS6, CS5, CS4, CS3, CS2, CS, 7" be defined. Make sure that a path for this application is present on the "Applications" page of the "Settings" dialog, then try again.

Comments
Er... You mean this product? http://www.daz3d.com/render-studio-modular-1-4-scenes-for-poser
The Render STudio series is for Poser only, so if you bought it, you can't use it with DAZ Studio. It also states as much in the description for the product. I recommend that you open a ticket with Customer support to get a refund for the product.
For DAZ Studio, you'd need:
THe description says required SW = DAZ Studio 4.9. No where does it mention Poser. I have Render Studio Iray and still get same error.
http://www.daz3d.com/render-studio-modular-1-4-scenes-for-poser has compatible software Poser. The Modular 1-4 scenes for Poser WILL need Poser. They will NOT work in DAZ Studio, because the light sets are incompatible with Iray.
For the Iray file error: it wants to install the Photoshop files in the Photoshop directory. As you have no Photoshop installed, you'll have to fake a directory (or use the Gimp directory, id that is what you are using). Then, you have to add the software path to DIM. Click on the little cogwheel in the upper right corner, in the window that opens, select Applications. You can add the path where it is to install the Photoshop files there. Hopefully, the installation will work then.
The product will most likely need Photoshop to work properly. I'm not sure if it will work in Gimp, as there seem to be some scripts involved.
Further to what BeeMKay has said, there are two separate issues.
Issue #1:
The original Render Studio line of products, which were migrated over to the DAZ store from the Runtime DNA store following the merger of the two companies, were designed to work in various versions of Poser. This is stated clearly in the product descriptions for these older products. Because DAZ Studio and Poser handle lighting differently, and the Render Studio products are primarily lighting products, they will not work properly in DAZ Studio. It should be noted that the foreging applies to the original line of Render Studio products that came from Runtime DNA, which includes the Render Studio Modular 1-4 + Scenes for Poser that you mentioned in your first post. The issue with Photoshop that you have experienced in attempting to install the package, bearing in mind that it is a bundle containing multiple individual products, is largely associated with one part of that package, specifically Render Studio Modular 1-4 + Scenes for Poser 4-Hollywood PS Action. However, none of that really matters if you are using DAZ Studio and do not have Poser, since none of the package will work correctly in DAZ Studio even if it did install. It is of no use to you anyway.
Issue #2:
Render Studio Iray is a different and separate product from that mentioned in Issue #1. It is designed specifically to be used in DAZ Studio, employing lighting also designed for the Iray render engine. It has nothing to do with the earlier products. If you are getting the same error message relating to Photoshop in attempting to install it, I am uncertain why, as there should be no need for Photoshop to use this version that I know of. If you are getting this error in attempting to install this newer version, you may need to file a bug report with support.