hi,
if it is security warnining like 'unable to verify supplier' just ignore and continue instsllation.
if any other error pls give details. ill help u
macho also it'll give you a security error if you try to install a software when the phone operating system(the platform version) doesnt match for the software.
because in nokia they have different platforms and different versions of those platforms.
eg: S60 2nd edition, S60 3rd edition, S40....etc
so you have to check whether what was the platform the software was made to run under.