Remote Desktop environment cannot find file

this problem similar http://social.technet.microsoft.com/forums/en-us/winserverts/thread/8ed2392e-b8f0-42a6-bb2e-f5854cd583bf/. need able launch program remote desktop (r6.0) but can't have client provide complete path executable before-hand (installation can occur in location).

in 2003, solved problem adding executable's installation location path environment variable, seems ignored 2008 (standard edition).

settings used follows:
at tab environment marked start following program @ logon checkbox.
program file name: app.exe
start in: <empty>

the error returned was:
the system cannot find file specified app.exe

i tried installing application remoteapp program, didn't seem help.

so have on server side application found without requiring client know full path?

regards,
hansw

ps: an additional side-question:
1) whole start following program @ logon ignored unless had terminal services role installed. there other way accomplish this? wasn't intending install license server , ts complains this, i'd prefer avoid warnings.

so solved main problem. had app installer define specific environment variable, %applocation%, , changed invocation to:

program file name: "%applocation%\app.exe"

of course, work %programfiles%, believe rong's reply suggesting.

that still leaves me problem mentioned in ps. need terminal services role installed in order start following program @ logon to not ignored?

Windows Server  >  Remote Desktop Services (Terminal Services)