If you are experiencing any issues with printing to an HP printer after updating to Acrobat 9.4.2 here are some temporary suggestions from Atul Agarwal and Atanu Dhar of Adobe Systems.
If you are facing an issue of print not working on Acrobat 9.4.2 on HP printers. Please follow the workarounds mentioned below:
We realize the importance of the issue and hence we are working closely to deliver a solution across to you all. Before we could provide a permanent solution/fix for this problem. You may please use the following workarounds for time being.
1) Right Click on the PDF document available on your machine and the Print gets fired on to the default printer. (To set the default printer, please go to printers & faxes and the right click on the printer of your choice and select set as the default printer)
2) Open the printer queue from Printers and Faxes and drag the PDF document in the printer queue.
3) This one seems to resolve the issue consistently. Update the Printer Driver to the latest available release. Open the PDF document in Acrobat. Launch the Print dialog and click properties button (on top right side) and the press ok to come out of the properties dialog box. Now, print the document. However, every time you re-launch the application then you may have to repeat the process of clicking the properties button and come out of it.
PS: The 3rd workaround might just work directly for certain users without even updating the printer driver due to the fact that the latest driver version might already be installed on your machine.
4) Go to the installation directory of Acrobat (i.e., C:\Program Files\Adobe\Acrobat 9.0\Acrobat). Look for the file "Adobe.Acrobat.Dependencies.manifest"
Open it in a text editor like Notepad and delete the line file name="atl.dll" /. Reboot your machine after saving that file.
Be assured that a dedicated team is working hard to resolve this issue for you as soon as possible.
There is also a technical note on Printing problems|HP printers|Acrobat 9.4.2 that offers detailed solutions.