to install extract the ZIP into your Poland's seperate install's EAW folder (NOT INTO OAW!).

For OAW use, provided it can handle Savedata or SD folders in tandem with not broken up campaigns, you need to extract the zip into a temporary folder and rename the savedata folder to:
SD(space)(exact filename of your poland campaignfolder in OAW).
For further questions plz contact Mr. Jelly.

VBH

P.S. the files only allow proper play in quick or single mission mode and do not cure the campaign mode. 