I’ve bought a Motorola A925 smartphone, which seems to run Symbian UIQ in pretty much the same way as the Sony Ericsson P900, so I’m hoping you can help me. Some of the programs I want to try out simply won’t install. Do I need to ask every single developer for an A925-compatible version?

No, that shouldn’t be necessary. Without knowing the exact error message you’re seeing, we guess the problem is that the SIS installation files for these programs have been set up with a dependency on either or both of the P800 or P900. You can check this for yourself and hopefully solve the problem, by finding a friend with a P800 or P900 and copying ‘Z:\System\Install\SonyEricssonP90xPlatform.sis’ across to a similar folder on your internal (‘C’) disk. There’s no room here for a detailed file copying tutorial, but any decent file manager utility (e.g. SMan) should let you extract the file, beam it across and then move it to the right folder on your A925. It’s worth noting, as you already seem to have realised, that some programs simply won’t work on the A925 because of small hardware differences. In these cases, it’s down to the developer to come up with a new version