As Dariusz says, DOS can only see 8.3 names, including the directory or directories above where you have the program. Likely the directory name needs to be shortened. Note that the WPS (OS/2 graphical shell) will use an extended attribute, .longname if you use it to rename the directory, so perhaps copy or xcopy the directory to a short name at a OS/2 cmd prompt.
Another solution is to use a FAT32 volume, FAT32 will show a shortname like dir~tory.