There are a number of reasons that could cause an error when exporting a movie to file (read-access rights to avi file, issues with codec, etc.). Send the log file to us so that we can help troubleshoot.
Before your Movie Maker is fixed, you can always export the animation as an image sequence and then use an open source 3rd party tool to create a movie file from that image sequence. Here are two options:
Option 1: VirtualDub (free, but Windows only)
VirtualDub (http://virtualdub.sourceforge.net/) is for Windows only and was designed for creating and editing AVI files. Once you've installed the program, just do the following:
1. Open VirtualDub then click File > Open, then select the first image in the sequence.
2. Click Video > Frame Rate, to change the frame rate (once loaded).
3. Click File > Save as AVI to save.
Option 2: ImageJ (free and cross-platform)
ImageJ (https://imagej.nih.gov/ij/index.html) uses Java so is cross platform (Windows, Mac OSX and Unix). ImageJ/"Fiji" (a fuller featured version) can read and write many image formats, but only writes out one type of movie format - and that is AVI. Often AVI is all you'll want though (especially if you want a PowerPoint movie) and the instructions are as follows:
1. Copy all the images/frames you want in a single directory with nothing else, and make sure they are in alphabetical order. For example: "frame000.jpg", "frame001.jpg", etc.
2. Open ImageJ.
3. Click File > Import > Image Sequence, navigate to the desired directory and click Select. There are some nice options here for scaling etc.
4. Click File > Save As > AVI..., select your frames per second (25 is good if you have many frames) and save your AVI.
There are no options for AVI quality, but this is still very effective.