I must have posted it over one hundred times on this forum, but I am happy to copy over one of my typical responses to those who have the "PowerPC app not working in Lion or Mt. Lion" problem for your consideration:
Unfortunately you got caught up in the minor miracle of Rosetta. Originally licensed by Apple when it migrated from the PowerPC CPU platform that it had used from the mid-1990's until the Intel CPU platform in 2006, Rosetta allowed Mac users to continue to use their library of PPC software transparently in emulation.
However, Apple's license to continue to use this technology expired with new releases of OS X commencing with Lion (and now Mountain Lion). While educational efforts have been made over the last 6 years, the fact is that Rosetta was SO successful that many users were caught unaware UNTIL they upgraded to Lion or Mountain Lion.
Workarounds:
1. If your Mac will support it, restore OS X Snow Leopard;
2. If your Mac will support it, partition your hard drive or add an external hard drive and install Snow Leopard into it and use the "dual-boot" method to choose between your PowerPC software or Lion/Mt. Lion;
3. Upgrade your software to Intel compatible versions if they are available, or find alternative software that will open your data files, modify them and save them;
4. Install Snow Leopard Server (with Rosetta) into Parallels or VMWare Fusion for concurrent use of your PowerPC applications with Lion or Mt. Lion:
[click on image to enlarge]
Apple has now restarted to sell Snow Leopard Server at a 95% discount over its original price: only $19.99 + sales tax & shipping; telephone orders only, call 800-MYAPPLE (800-692-7753) - Apple Part Number: MC588Z/A
NOTE: Computer games with complex, 3D or fast motion graphics may not work well or at all in virtualization.
Workaround #3 appears to be the OP's best solution in this case.