Package Install via Market sometimes fails and gives seemingly random error message Some times when I install an application, the installation will fail.

However, the errors it throws are not only incorrect, but seemingly... random.

An example is, it'll fail and throw 'Insufficient storage space.' Blatant lie, I have plenty of space on the phone.

Another example is 'Package file is invalid.'

When I go to redownload the app, it usually installs just fine. On rarer occasions, it'll throw another (can't remember if it's the same) error, but then it'll install just fine.

I'm using stock market, on a stock Droid 3.
You can get 'Insufficient storage space' messages if you don't have enough space on the internal SD card for the market to be able to download the APK into a temp or data directory.  When you reboot your phone or exit from certain apps various caches/data directories are cleared, freeing up space on the internal SD card.  This is why this error appears 'randomnly' - because as you use and close apps, the amount of disk space changes.  There are several apps on the market that can force cache clean ups for you.

'Package file is invalid' can occur if you have disk errors or networking errors that corrupt the downloaded file.  This is why this error appears 'randomnly', as SD card file system issues or dropped/bad packets corrupting the file won't occur every time.  FYI, SD card file system errors are often a result of not unmounting the phone properly when connecting it via USB or by yanking the SD card from a reader without unmounting it first ("safely remove hardware" in Windows parlance)