How can DOS app perform illegal operation?

[Chapin]

I have a win98 system running some DOS apps (accpac, easypay, and dataeasy)this system prints to 3 local lpt ports, the problem is when accpac or easypay are accessed for the first time during the day and I try to print it will kick me right out of the program and the error message comes up "This program has performed an illegal operation" I go back into the apps and they will run fine all day, till next day when it happens again.
I have left the system on all night, it runs a schedule back up on colorado backup, it treats it as a restart, because the same problem appears the next morning.
Has any one experienced illegal operations in DOS apps? Any insight would be very helpful, Thanks.

[condor]

Basically this probelms happens because one application is trying to access amemory address already assigned to another application..

sorry I can't offer more help..

those cases often require the "hands on" approach..

[Mr_Miyagi]

Originally posted by Invisible_Man:
I have a win98 system running some DOS apps (accpac, easypay, and dataeasy)this system prints to 3 local lpt ports, the problem is when accpac or easypay are accessed for the first time during the day and I try to print it will kick me right out of the program and the error message comes up "This program has performed an illegal operation" I go back into the apps and they will run fine all day, till next day when it happens again.
I have left the system on all night, it runs a schedule back up on colorado backup, it treats it as a restart, because the same problem appears the next morning.
Has any one experienced illegal operations in DOS apps? Any insight would be very helpful, Thanks.

you should look in the direction of the "backup" and DOS... i have known the disconnection of "services" when doing scheduled tasks so that when returning the app in question is confused and crashes. the other theory i am leaning towards is the dos app does not like being "left" while windows takes control and does the backup; so when you return it crashes in protest!