Extra files need to be copied into your bottle 'windows/system for this application to install and run correctly.
I have tested and now regularly using kBilling 1.3.71 & 1.3.74 under Crossover 5.0.1 and 5.0.3, All seems to work as good as it was under Windows with the exception of the 'Check for kBilling updates' feature and the 'Open PDF' (needs external viewer i think). It has never crashed on me and runs as fast if not faster than it was under Windows.
1) Create a new win98 bottle, install IE6
2) You need to have access to an existing windows xp installation and copy the following files to your bottle 'windows/system/' directory :
\windows\system32\kernel32.dll
\windows\system32\ntdll.dll
\windows\system32\user32.dll
\windows\system32\gdi32.dll
\windows\system32\riched32.dll
\windows\system32\riched20.dll
\windows\system32\shell32.dll
\windows\system32\crtdll.dll
\windows\system32\comdlg32.dll
\windows\system32\wsock32.dll
\windows\system32\ws2_32.dll
\windows\system32\ws2help.dll
\windows\system32\winspool.drv
\windows\system32\uxtheme.dll
3) Install KBilling exe file using the 'un-supported software' option, enter your serial number when prompted.