Why do I get "not enough space" when I copy an APK file to /system/app?

I recently rooted my HTC Desire Bravo because I needed read/write access to /system/app in order to be able to copy an APK file there. I wrote here on stackexchange on the best solution to root the Desire and got pointed to Unrevoked. Everything worked fine and typing "su" in the adb shell gives me nice root access. I re-mounted /system like mount -o rw,remount -t yaffs2 /dev/block/mtdblock3 /system That worked. However, trying to copy my APK file using adb push MyApp.apk /system/app/ didn't work and gave me a "permission denied". Alternatively I therefore pushed the app to /sdcard first and wanted to do a cat /sdcard/MyApp.apk > /system/app/MyApp.apk That approach has worked just perfectly on my rooted HTC Hero, on the Desire however it gives me > "Cannot create /system/app/MyApp.apk: > not enough memory" Does anyone have a clue on what could be the problem here? How can I push my app to the system folder so that it installs properly?