Sounds like you had it set to download to the SD card. If that is the case, then the only way to fix that is to change it over to download and install to the phone's "Internal" storage.
If, by any chance, you had set the card to be "Internal" storage as well, then that card will only be readable by that phone.
If it was just changed to download to there, you can change that option in the app that you did the downloading through, or in the phone's "Settings". If it was set to be "Internal" storage, then you would have to reinsert the SD card, move all the files off the card (including apps) and then reset the card as normal "External" storage before removing it again and reinserting the SIM card. In this case you may have a problem if there isn't enough room on the phone itself to hold the stuff from the SD card. However, should you try to change the storage from the card (as "Internal") to just downloading to the phone without making the change on the card itself, then when you go to reinsert the SD card, you won't have access to anything on it.